Blood test Health Dictionary

Blood pressure is that pressure which must be applied to an artery in order to stop the pulse beyond the point of pressure. It may be roughly estimated by feeling the pulse at the wrist, or accurately measured using a SPHYGMOMANOMETER. It is dependent on the pumping force of the heart, together with the volume of blood, and on the elasticity of the blood vessels.

The blood pressure is biphasic, being greatest (systolic pressure) at each heartbeat and falling (diastolic pressure) between beats. The average systolic pressure is around 100 mm Hg in children and 120 mm Hg in young adults, generally rising with age as the arteries get thicker and harder. Diastolic pressure in a healthy young adult is about 80 mm Hg, and a rise in diastolic pressure is often a surer indicator of HYPERTENSION than is a rise in systolic pressure; the latter is more sensitive to changes of body position and emotional mood. Hypertension has various causes, the most important of which are kidney disease (see KIDNEYS, DISEASES OF), genetic predisposition and, to some extent, mental stress. Systolic pressure may well be over 200 mm Hg. Abnormal hypertension is often accompanied by arterial disease (see ARTERIES, DISEASES OF) with an increased risk of STROKE, heart attack and heart failure (see HEART, DISEASES OF). Various ANTIHYPERTENSIVE DRUGS are available; these should be carefully evaluated, considering the patient’s full clinical history, before use.

HYPOTENSION may result from super?cial vasodilation (for example, after a bath, in fevers or as a side-e?ect of medication, particularly that prescribed for high blood pressure) and occur in weakening diseases or heart failure. The blood pressure generally falls on standing, leading to temporary postural hypotension – a particular danger in elderly people.... blood pressure

The principal reproductive androgen of males, largely responsible for sexual maturation, some libido, and a range of metabolic reactions that, while supplying short-term strengths, creates a long-term fragility and brittleness if not in balance with less garish but more sustainable metabolic buffers. It is secreted by the Leydig cells of the testes, as well as smaller amounts in the adrenal cortices of both sexes. It is made under the direction of LH from the pituitary, and, if oversecreted, can be inhibited by sperm-producing cells, diminished pituitary support, and a rise in blood levels of its waste-product, stored in adipose tissues...estradiol... testosterone

Blood consists of cellular components suspended in plasma. It circulates through the blood vessels, carrying oxygen and nutrients to the organs and removing carbon dioxide and other waste products for excretion. In addition, it is the vehicle by which hormones and other humoral transmitters reach their sites of action.

Composition The cellular components are red cells or corpuscles (ERYTHROCYTES), white cells (LEUCOCYTES and lymphocytes – see LYMPHOCYTE), and platelets.

The red cells are biconcave discs with a diameter of 7.5µm. They contain haemoglobin

– an iron-containing porphyrin compound, which takes up oxygen in the lungs and releases it to the tissue.

The white cells are of various types, named according to their appearance. They can leave the circulation to wander through the tissues. They are involved in combating infection, wound healing, and rejection of foreign bodies. Pus consists of the bodies of dead white cells.

Platelets are the smallest cellular components and play an important role in blood clotting (see COAGULATION).

Erythrocytes are produced by the bone marrow in adults and have a life span of about 120 days. White cells are produced by the bone

marrow and lymphoid tissue. Plasma consists of water, ELECTROLYTES and plasma proteins; it comprises 48–58 per cent of blood volume. Plasma proteins are produced mainly by the liver and by certain types of white cells. Blood volume and electrolyte composition are closely regulated by complex mechanisms involving the KIDNEYS, ADRENAL GLANDS and HYPOTHALAMUS.... blood

A blood clot arises when blood comes into contact with a foreign surface – for example, damaged blood vessels – or when tissue factors are released from damaged tissue. An initial plug of PLATELETS is converted to a de?nitive clot by the deposition of FIBRIN, which is formed by the clotting cascade and erythrocytes. (See COAGULATION.)... blood clot

The number of each of the cellular components per litre of blood. It may be calculated using a microscope or by an automated process.... blood count

See TRANSFUSION – Transfusion of blood.... blood transfusion

See SEPTICAEMIA.... blood-poisoning

A skin test to ?nd out if a person is immune to TUBERCULOSIS. TUBERCULIN (a preparation derived from the TUBERCLE bacillus) is injected via punctures in the skin of the forearm, using a spring-loaded gunlike instrument with six very short needles set in circular form. A positive test is indicated by a red raised reaction of the skin: this means that the subject is immune. If the result is negative, the subject can be given BCG VACCINE.... heaf test

A test for TUBERCULOSIS. It consists in injecting into the super?cial layers of the skin (i.e. intradermally) a very small quantity of old TUBERCULIN which contains a protein ANTIGEN to TB. A positive reaction of the skin – swelling and redness – shows that the person so reacting has been infected at some time in the past with Mycobacterium tuberculosis. However, it does not mean that such a person is suffering from active tuberculosis.... mantoux test

This is used to identify possible substances that may be causing a patient’s ALLERGY. Small amounts of di?erent substances are placed on the skin – usually of the back or arm. If the patient is allergic then a red ?are and swelling will appear, usually within about 15 minutes. Sometimes the reaction may take longer – up to three days – to develop.... patch test

A psychological test (see PSYCHOLOGY) for investigating personality and disorders of personality. Also called the ‘ink blot test’, it is now rarely used. It was devised by a Swiss psychiatrist, Hermann Rorschach (1884–1922), who determined individuals’ reactions to a series of symmetrical ink-blots, ten in number and standardised by him.... rorschach test

See TESTICLE.... testis

(1) The name given to a gastric-function test, involving injection of HISTAMINE – a powerful stimulator of gastric juice, or pentagastin. After the stimulant has been injected, the digestive juices are withdrawn through a stomach tube (inserted through the nose and throat) and their volume and chemistry measured. A similar test is used to assess the working of the PANCREAS.

(2) The second meaning (also called test feed) applies to a diagnostic procedure for congenital PYLORIC STENOSIS, whereby a paediatrician feels over the baby’s abdomen while he or she is feeding. The pyloric mass can be felt as a ?rm swelling with the consistency of a squash ball, which comes and goes under the examiner’s ?ngers.... test meal

Every man has two testicles or testes which are the sexual glands. In the fetus, they develop in the abdomen, but before birth they descend into a fold or pouch of skin known as the SCROTUM. Each testicle consists of up to 1,000 minute tubes lined by cells from which the spermatozoa (see SPERMATOZOON) are formed. Around 4·5 million spermatozoa are produced per gram of testicle per day. These tubes communicate with one another near the centre of the testicle, and are connected by a much coiled tube, the EPIDIDYMIS, with the ductus, or VAS DEFERENS, which enters the abdomen and passes on to the base of the bladder. This duct, after joining a reservoir known as the seminal vesicle, opens, close to the duct from the other side of the body, into the URETHRA where it passes through the PROSTATE GLAND. Owing to the convolutions of these ducts leading from the testicles to the urethra, and their indirect route, the passage from testicle to urethra is over 6 metres (20 feet) in length. In addition to producing spermotozoa, the testicle also forms the hormone TESTOSTERONE which is responsible for the development of male characteristics.... testicle

See BLOOD GROUPS.... abo blood groups

A department in which blood products are prepared, stored, and tested prior to transfusion into patients.... blood bank

A functional, semi-permeable membrane separating the brain and cerebrospinal ?uid from the blood. It allows small and lipid-soluble molecules to pass freely but is impermeable to large or ionised molecules and cells.... blood brain barrier

See ERYTHROCYTES and LEUCOCYTES.... blood corpuscle

An individual who donates his or her own blood for use in patients of compatible blood group who require transfusion.... blood donor

Speci?cally, this describes the measurement of the tensions of oxygen and carbon dioxide in blood. However, it is commonly used to describe the analysis of a sample of heparinised arterial blood for measurement of oxygen, carbon dioxide, oxygen saturation, pH, bicarbonate, and base excess (the amount of acid required to return a unit volume of the blood to normal pH). These values are vital in monitoring the severity of illness in patients receiving intensive care or who have severe respiratory illness, as they provide a guide to the e?ectiveness of oxygen transport between the outside air and the body tissues. Thus they are both a guide to whether the patient is being optimally ventilated, and also a general guide to the severity of their illness.... blood gases

Tube through which blood is conducted from or to the heart. Blood from the heart is conducted via arteries and arterioles through capillaries and back to the heart via venules and then veins. (See ARTERIES and VEINS.)... blood vessel

A test for vestibular function (see EAR). It is performed by irrigating the external auditory meatus of the ear with alternate cold and hot water. This usually stimulates the vestibular apparatus, causing nystagmus (see DIABETES MELLITUS – Diabetic eye disease). If the vestibular apparatus is affected by disease, the response may be absent or reduced.... caloric test

People are divided into four main groups in respect of a certain reaction of the blood. This depends upon the capacity of the serum of one person’s blood to cause the red cells of another’s to stick together (agglutinate). The reaction depends on antigens (see ANTIGEN), known as agglutinogens, in the erythrocytes and on ANTIBODIES, known as agglutinins, in the serum. There are two of each, the agglutinogens being known as A and B. A person’s erythrocytes may have (1) no agglutinogens, (2) agglutinogen A, (3) agglutinogen B, (4) agglutinogens A and B: these are the four groups. Since the identi?cation of the ABO and Rhesus factors (see below), around 400 other antigens have been discovered, but they cause few problems over transfusions.

In blood transfusion, the person giving and the person receiving the blood must belong to the same blood group, or a dangerous reaction will take place from the agglutination that occurs when blood of a di?erent group is present. One exception is that group O Rhesus-negative blood can be used in an emergency for anybody.

	Agglutinogens	Agglutinins	Frequency
	in the	in the	in Great
Group	erythrocytes	plasma	Britain
AB	A and B	None	2 per cent
A	A	Anti-B	46 per cent
B	B	Anti-A	8 per cent
O	Neither	Anti-A and	44 per cent
	A nor B	Anti-B

Rhesus factor In addition to the A and B agglutinogens (or antigens), there is another one known as the Rhesus (or Rh) factor – so named because there is a similar antigen in the red blood corpuscles of the Rhesus monkey. About 84 per cent of the population have this Rh factor in their blood and are therefore known as ‘Rh-positive’. The remaining 16 per cent who do not possess the factor are known as ‘Rh-negative’.

The practical importance of the Rh factor is that, unlike the A and B agglutinogens, there are no naturally occurring Rh antibodies. However, such antibodies may develop in a Rh-negative person if the Rh antigen is introduced into his or her circulation. This can occur (a) if a Rh-negative person is given a transfusion of Rh-positive blood, and (b) if a Rh-negative mother married to a Rh-positive husband becomes pregnant and the fetus is Rh-positive. If the latter happens, the mother develops Rh antibodies which can pass into the fetal circulation, where they react with the baby’s Rh antigen and cause HAEMOLYTIC DISEASE of the fetus and newborn. This means that, untreated, the child may be stillborn or become jaundiced shortly after birth.

As about one in six expectant mothers is Rh-negative, a blood-group examination is now considered an essential part of the antenatal examination of a pregnant woman. All such Rh-negative expectant mothers are now given a ‘Rhesus card’ showing that they belong to the rhesus-negative blood group. This card should always be carried with them. Rh-positive blood should never be transfused to a Rh-negative girl or woman.... blood groups

A sensitive test that detects ANTIBODIES to the body’s red cells (see ERYTHROCYTE). There are two methods: one – the direct method – identi?es those antibodies that are bound to the cells; the other, indirect, method identi?es those circulating unattached in the serum.... coomb’s test

Skin test used to determine the immune s tatus to scarlet fever.... dick test

A procedure performed during a mother’s labour in which a blood sample is taken from a vein in the scalp of the FETUS. This enables tests to be performed that indicate whether the fetus is, for example, suffering from a shortage of oxygen (HYPOXIA). If so, the obstetrician will usually accelerate the baby’s birth.... fetal blood sampling

Sanguinaria canadensis. N.O. Papaveraceae.

Habitat: Widely distributed throughout North America.

Features ? Root reddish-brown, wrinkled lengthwise, about half-inch thick. Fracture short. Section whitish, with many small, red resin cells which sometimes suffuse the whole. Heavy odour, bitter and harsh to the taste.

Part used ? Root.

Action: Stimulant, tonic, expectorant.

Pulmonary complaints and bronchitis. Should be administered in whooping-cough and croup until emesis occurs. The powdered root is used as a snuff in nasal catarrh, and externally in ringworm and other skin eruptions. The American Thomsonians use it in the treatment of adenoids. Dose, 10 to 20 grains of the powdered root.... blood root

A way of assessing the body’s e?ciency at metabolising GLUCOSE. The test is used in the diagnosis of DIABETES MELLITUS. The patient is starved for up to 16 hours, after which he or she is fed glucose by mouth. The concentrations of glucose in the blood and urine are then measured at half-hour intervals over a period of two hours.... glucose-tolerance test

A standardised procedure of mental assessment to determine an individual’s intellectual ability. The result is produced as a score termed the INTELLIGENCE QUOTIENT (IQ). The Wechsler Adult Intelligence Scale (WAIS) and one for children, the Wechsler Intelligence Scale for Children (WICS), are commonly used, as is the Stanford-Binet Scale. Assessments are made for educational purposes and to help in the diagnoses of people with possible mental retardation or intellectual deterioration.... intelligence test

The characteristic histological test used for the diagnosis of SARCOIDOSIS. The test involves an intradermal injection of sarcoid SPLEEN tissue. If positive, non-caseating granulomata (see GRANULOMA) are seen at the injection site in 4– 6 weeks. A positive test is highly speci?c for sarcoid, but if negative, this would not be excluded.... kveim test

See CERVICAL SMEAR.... papanicolaou test

See ERYTHROCYTES; BLOOD.... red blood cell

See EMBRYO TRANSFER.... test-tube baby

There are several tests for pregnancy (see PREGNANCY AND LABOUR) in its early stages, and these can be done on blood or urine; some of the urine tests may be carried out at home. Most tests are based on the detection of HUMAN CHORIONIC GONADOTROPHIN (HCG) in the woman’s urine. They are nearly 100 per cent accurate and may show positive as early as 30 days after the ?rst day of the last normal period.

The haemagglutination inhibition test This, and the subsequent tests to be mentioned, are known as immunological tests. They are based upon the e?ect of the urine from a pregnant woman upon the interaction of red blood cells, which have been sensitised to human gonadotrophin, and anti-gonadotrophin serum. They have the great practical advantage of being performed in a test-tube or even on a slide. Because of their ease and speed of performance, a result can be obtained in two hours.

Enzyme-linked immunosorbent assay (ELISA) This is the basis of many of the pregnancy-testing kits obtainable from pharmacies. It is a highly sensitive antibody test and can detect very low concentrations of human chorionic gonadotrophin. Positive results show up as early as ten days after fertilisation – namely, four days before the ?rst missed period.

Ultrasound The fetal sac can be detected by ULTRASOUND from ?ve weeks, and a fetal echo at around six or seven weeks (see also PRENATAL SCREENING OR DIAGNOSIS).... pregnancy tests

Tests to assess how the LUNGS are functioning. They range from simple spirometry (measuring breathing capacity) to sophisticated physiological assessments.

Static lung volumes and capacities can be measured: these include vital capacity – the maximum volume of air that can be exhaled slowly and completely after a maximum deep breath; forced vital capacity is a similar manoeuvre using maximal forceful exhalation and can be measured along with expiratory ?ow rates using simple spirometry; total lung capacity is the total volume of air in the chest after a deep breath in; functional residual capacity is the volume of air in the lungs at the end of a normal expiration, with all respiratory muscles relaxed.

Dynamic lung volumes and ?ow rates re?ect the state of the airways. The forced expiratory volume (FEV) is the amount of air forcefully exhaled during the ?rst second after a full breath – it normally accounts for over 75 per cent of the vital capacity. Maximal voluntary ventilation is calculated by asking the patient to breathe as deeply and quickly as possible for 12 seconds; this test can be used to check the internal consistency of other tests and the extent of co-operation by the patient, important when assessing possible neuromuscular weakness affecting respiration. There are several other more sophisticated tests which may not be necessary when assessing most patients. Measurement of arterial blood gases is also an important part of any assessment of lung function.... pulmonary function tests

The screening of apparently healthy people to identify those who may have treatable diseases. Cervical smears are done when screening women to detect if they have cancer or precancer of the neck of the womb (cervix). Newborn babies are screened for hip dislocation. Screening tests are not designed to diagnose individual persons, but rather to divide a population into a large number at low risk and a small number at high risk of a condition. This allows clinicians to concentrate on a sub-section of the population. All screening tests produce false negative and false positive results, a problem often misunderstood by those at the receiving end. Factors to be assessed when planning screening procedures include the severity, frequency and distribution of the disease, and the availability and e?ectiveness of treatment. Convenience, safety, sensitivity and cost should also be assessed. In the United Kingdom the government has supported the extension of screening procedures for breast cancer, cervical cancer, hypertension and diabetes. (See PREVENTIVE MEDICINE.)... screening test

A test done on SERUM from patients with JAUNDICE to discover whether the excess BILIRUBIN in the blood – which causes the jaundice

– is conjugated or unconjugated. If conjugated, this indicates that HAEMOLYSIS is causing the jaundice; if unconjugated, disease of the LIVER or BILE DUCT is the likely diagnosis.... van den bergh test

Most vision tests examine a person’s sharpness of VISION (visual acuity) and often of the ?eld of vision (see VISION, FIELD OF). Refraction tests assess whether a person has an error that can be corrected with glasses such as ASTIGMATISM, HYPERMETROPIA or MYOPIA. Visual acuity is tested using a Snellen chart when the patient tries to read letters of di?ering standard sizes from 6 metres away. The optician will prescribe lenses to correct any defects detected by vision tests.... vision tests

See LEUCOCYTES.... white blood cell

See blood glucose.... blood sugar

The process of blood solidification. Clotting is important in stemming bleeding from damaged blood vessels. However, unwanted blood clotting can occur inside major blood vessels and cause a myocardial infarction (heart attack) or stroke (see thrombosis).

When a blood vessel is damaged, it constricts immediately to reduce blood flow to the area. The damage sets off a series of chemical reactions that lead to the formation of a clot to seal the injury. First, platelets around the injury site are activated, becoming sticky and adhering to the blood-vessel wall. Then, the activated platelets release chemicals, which, in turn, activate blood clotting factors. These factors, together with vitamin K, act on fibrinogen and convert it to fibrin. Strands of fibrin form a meshwork, which traps red blood cells to form a clot.

There are several anticlotting mechanisms to prevent the formation of unwanted clots. These include prostacyclin (a prostaglandin), which prevents platelet aggregation, and plasmin, which breaks down fibrin (see fibrinolysis). Blood flow washes away active coagulation factors; and the liver deactivates excess coagulation factors.

Defects in blood clotting may result in bleeding disorders.

Excessive clotting (thrombosis) may be due to an inherited increase or defect in a coagulation factor (see factor V), the use of oral contraceptives, a decrease in the level of enzymes that inhibit coagulation, or sluggish blood flow through a particular area.

Treatment is usually with anticoagulant drugs such as heparin or warfarin.... blood clotting

A testis that is drawn up.... testis, retractile

A rare inherited condition in which a genetic male with internal testes has the external appearance of a female. The syndrome is a form of intersex and is the most common form of male pseudohermaphroditism.

The cause is a defective response of the body tissues to testosterone.

The causative genes are carried on the X chromosome, and so females can be carriers. Affected individuals appear to be girls throughout childhood, and most develop female secondary sexual characteristics at puberty; but amenorrhoea occurs, and a diagnosis is usually made during investigations to find its cause. Chromosome analysis shows the presence of male chromosomes and blood tests show male levels of testosterone. Treatment of testicular feminization syndrome involves surgical removal of the testes, to prevent cancerous change in later life, and therapy with oestrogen drugs. An affected person is not fertile but can live a normal life as a woman.... testicular feminization syndrome

See TRANSFUSION – Transfusion of blood.... autologous blood transfusion

Fixed dilated pupils of the eyes

Absent CORNEAL REFLEX

Absent VESTIBULO-OCULAR REFLEX

No cranial motor response to somatic (physical) stimulation

Absent gag and cough re?exes

No respiratory e?ort in response to APNOEA despite adequate concentrations of CARBON DIOXIDE in the arterial blood.... b nosed. the test for brain-stem death are:

A test for gauging the e?ciency of the balancing mechanism (the vestibular apparatus) by applying hot or cold air or water to the external ear.... barany’s test

See VENESECTION.... blood-letting

See ANAEMIA; LEUKAEMIA; LYMPHOMA; MYELOMATOSIS; THROMBOSIS.... blood, diseases of

A medico-legal defence for a clinician accused of failing to provide an acceptable standard of care for one of his or her quali?cation and experience. The defence is that a responsible body of medical practitioners would have taken the same action, even though others would have acted di?erently. The precise size of a ‘responsible body’ has not been de?ned. The test has been modi?ed following a case referred to as Bolitho, in which it was held that the Bolam defence failed if it could be shown that the actions relied upon, although shown to be carried out by some responsible doctors, were nonetheless illogical.... bolam test

In surveys, studying the process of interpretation of questions and the formation and reporting of responses by respondents to learn how to make the questions more accurately obtain the data the questionnaire is seeking.... cognitive testing

This is the main cause of anaemia in infections. The micro-organism responsible for the infection has a deleterious e?ect upon the blood-forming organs, just as it does upon other parts of the body.

Toxins. In conditions such as chronic glomerulonephritis (see KIDNEYS, DISEASES OF) and URAEMIA there is a severe anaemia due to the e?ect of the disease upon blood formation.

Drugs. Certain drugs, such as aspirin and the non-steroidal anti-in?ammatory drugs, may cause occult gastrointestinal bleeding.... defective blood formation

Love, Protection, Exorcism, Potency... dragons blood

See GENETIC SCREENING.... gene testing

The course of the circulation is as follows: the veins pour their blood, coming from the head, trunk, limbs and abdominal organs, into the right atrium of the HEART. This contracts and drives the blood into the right ventricle, which then forces the blood into the LUNGS by way of the pulmonary artery. Here it is contained in thin-walled capillaries, over which the air plays freely, and through which gases pass readily out and in. The blood gives o? carbon dioxide (CO2) and takes up oxygen (see RESPIRATION), and passes on by the pulmonary veins to the left atrium of the heart. The left atrium expels it into the left ventricle, which forces it on into the aorta, by which it is distributed all over the body. Passing through capillaries in the various tissues, it enters venules, then veins, which ultimately unite into two great veins, the superior and the inferior vena cava, these emptying into the right atrium. This complete circle is accomplished by any particular drop of blood in about half a minute.

In one part of the body there is a further complication. The veins coming from the bowels, charged with food material and other products, split up, and their blood undergoes a second capillary circulation through the liver. Here it is relieved of some food material and puri?ed, and then passes into the inferior vena cava, and so to the right atrium. This is known as the portal circulation.

The circle is maintained always in one direction by four valves, situated one at the outlet from each cavity of the heart.

The blood in the arteries going to the body generally is bright red, that in the veins dull red in colour, owing to the former being charged with oxygen and the latter with carbon dioxide (see RESPIRATION). For the same reason the blood in the pulmonary artery is dark, that in the pulmonary veins is bright. There is no direct communication between the right and left sides of the heart, the blood passing from the right ventricle to the left atrium through the lungs.

In the embryo, before birth, the course of circulation is somewhat di?erent, owing to the fact that no nourishment comes from the bowels nor air into the lungs. Accordingly, two large arteries pass out of the navel, and convey blood to be changed by contact with maternal blood (see PLACENTA), while a large vein brings this blood back again. There are also communications between the right and left atria, and between pulmonary artery and aorta. The latter is known as the ductus arteriosus. At birth all these extra vessels and connections close and rapidly shrivel up.... circulatory system of the blood

A test for colour vision, introduced by a Japanese doctor, comprising several plates with round dots of di?erent colours and sizes. It is also the name of a type of blood test for SYPHILIS.... ishihara’s test

As a result of trauma. This is perhaps the simplest example of all, when, as a result of an accident involving a large artery, there is severe haemorrhage.

Menstruation. The regular monthly loss of blood which women sustain as a result of menstruation always puts a strain on the blood-forming organs. If this loss is excessive, then over a period of time it may lead to quite severe anaemia.

Childbirth. A considerable amount of blood is always lost at childbirth; if this is severe, or if the woman was anaemic during pregnancy, a severe degree of anaemia may develop.

Bleeding from the gastrointestinal tract. The best example here is anaemia due to ‘bleeding piles’ (see HAEMORRHOIDS). Such bleeding, even though slight, is a common cause of anaemia in both men and women if maintained over a long period of time. The haemorrhage may be more acute and occur from a DUODENAL ULCER or gastric ulcer (see STOMACH, DISEASES OF), when it is known as haematemesis.

Certain blood diseases, such as PURPURA and HAEMOPHILIA, which are characterised by bleeding.... loss of blood

See under TESTICLE, DISEASES OF.... maldescended testis

The determination of eligibility for a publicly financed programme on the basis of an applicant’s income and assets (means).... means test

This body manages regional TRANSFUSION centres. Among its aims are the maintenance and promotion of blood and blood products based on a system of voluntary donors; implementing a cost-e?ective national strategy for ensuring adequate supplies of blood and its products to meet national needs; and ensuring high standards of safety and quality.... national blood authority

A test for MONONUCLEOSIS which is based upon the fact that patients with this disease develop ANTIBODIES which agglutinate sheep red blood cells.... paul-bunnell test

These have almost completely replaced BONE MARROW TRANSPLANT, used to treat malignancies such as LEUKAEMIA and LYMPHOMA for the past 20 years. The high doses of CHEMOTHERAPY or RADIOTHERAPY used to treat these diseases destroy the bone marrow which contains stem cells from which all the blood cells derive. In 1989 stem cells were found in the blood during recovery from chemotherapy. By giving growth factors (cytokines), the number of stem cells in the blood increased for about three to four days. In a peripheral-blood stem-cell transplant, these cells can be separated from the peripheral blood, without a general anaesthetic. The cells taken by either method are then frozen and returned intravenously after the chemotherapy or radiotherapy is completed. Once transplanted, the stem cells usually take less than three weeks to repopulate the blood, compared to a month or more for a bone marrow transplant. This means that there is less risk of infection or bleeding during the recovery from the transplant. The whole procedure has a mortality risk of less than 5 per cent – half the risk of a bone marrow transplant.... peripheral-blood stem-cell transplants

A test for INFERTILITY. A specimen of cervical mucus, taken up to 24 hours after coitus (during the post-ovulatory phase of the menstrual cycle), is examined microscopically to assess the motility of the sperms. If motility is above a certain level, then sperms and mucus are not interacting abnormally – thus eliminating one cause of sterility.... post-coital test

A hearing test in which a vibrating tuning fork is placed on the mastoid process (see EAR). When the subject can no longer hear the ringing, it is placed beside the ear. Normal subjects can then hear the noise once more, but in people with conductive DEAFNESS, air conduction does not persist after bone conduction has ceased. It can help to distinguish between nerve (sensorineural) and conduction deafness.... rinnes test

A tube of thin glass closed at one end, which is used for observing chemical reactions or for bacterial culture.... test-tube

A mathematical formula (or function) that is used to determine if the difference between outcomes of a treatment or intervention and a control group is great enough to conclude that the difference is statistically significant. Statistical tests generate a value that is associated with a particular P value. Among the variety of common statistical tests are: F, t, Z, and chi-square. The choice of a test depends upon the conditions of the study, e.g. what type of outcome variable is used, whether or not the subjects are randomly selected from a larger population, and whether it can be assumed that the outcome values of the population have a normal distribution or other type of distribution.... statistical test

A positive tourniquet test with scattered fine petechiae is one of the earliest clinical signs in dengue haemorrhagic fever.... tourniquet test

See under TESTICLE, DISEASES OF.... undescended testis

Venereal Diseases Research Laboratory Test. One of the non-treponemal reaginic tests for syphilis.... vdrl test

As a natural beverage, a cup of tea brings you many health benefits. One of them is related to blood pressure. Based on the type of tea you drink, it can help lower your blood pressure. Find out more about teas for blood pressure! Problems with blood pressure Blood pressure represents the pressure made by the circulating blood on the walls of the blood vessels. However, problems appear in the case of hypertension and hypotension. Hypertension is a medical condition caused by a high blood pressure, while hypotension is caused by a low blood pressure. Both can be treated with one of the various types of tea for blood pressure. Tea for high blood pressure If you’ve got problems with hypertension (high blood pressure), hibiscus tea can help, as it is known to lower blood pressure. You can also pick one of these herbal teas: chrysanthemum tea, flax tea, periwinkle tea, red root tea, self-heal tea, white peony root tea, valerian tea, or wild cherry bark tea. You can also drink hyssop tea, barberry tea, and rosemary tea, regardless of the blood pressure problem. These three teas will help regulate your blood pressure and reduce the risk of getting either high or low blood pressure problems. Tea for low blood pressure In the case of hypotension (low blood pressure), some of the teas you can try include lovage tea, ephedra tea, wu yi tea, cat’s claw tea, vervain tea, or wheatgrass tea. Black tea can help too, though you have to be careful with it as it has a high content of caffeine. Forbidden teas for blood pressure problems There are several teas which you should avoid drinking, no matter if you’ve got problems with high blood pressure or low blood pressure. The list of teas you shouldn’t drink includes arnica tea, black cohosh tea, gentian tea, juniper tea, lobelia tea, red ginseng tea, sage tea, stone root tea, and yohimbe tea. Also, generally it isn’t recommended to drink tea that lowers blood pressure if you’ve got hypotension, or tea that leads to high blood pressure if you’ve got hypertension. Whether you’ve got problems with high blood pressure or low blood pressure, try a more natural treatment: choose one of the many teas for blood pressure!... tea for blood pressure

A test with a tuning fork that is used to assess a person’s DEAFNESS.... weber’s test

An agglutination test used in the laboratory to diagnose rickettsial diseases. It depends on a nonspecific cross reaction between antibodies produced by the rickettsial infection with the OX-2, OX-19 and OXK antigens of the Gram negative rod, Proteus.... weil-felix test

A serological test used to detect antibodies in the diagnosis of typhoid. Antigens detected are the O (somatic), H (flagellar) and Vi (virulence) antigens.... widal test

See: BLEEDING (haemoptysis). ... coughing of blood

Popular blood tonic of the 1930s, 1940s and 1950s. Ingredients: Liquid Extract Liquorice 5 per cent, Infusion Gentian Co Conc 10 per cent, Infusion Senna Conc 5 per cent. And 25 per cent alcoholic extractive from Burdock 5 per cent, Red Clover 5 per cent, Queen’s root 2.5 per cent, Yellow Dock root 1.25 per cent, Poke root 2.5 per cent, Sarsaparilla 2.5 per cent. (Carter Bros) ... glentona herbal blood purifier

The first intelligence test that attempted to measure higher mental functions, devised in 1905.... binet test

Tests to screen for and diagnose bleeding disorders, usually resulting from deficiencies or abnormalities of blood coagulation factors or of platelets (see blood clotting). Tests are also used to monitor treatment with anticoagulant drugs.... blood-clotting tests

The SCROTUM may be affected by various skin diseases, particularly eczema (see DERMATITIS) or fungal infection. A HERNIA may pass into the scrotum. Defective development of the testicles may lead to their retention within the abdomen, a condition called undescended testicle.

Hydrocoele is a collection of ?uid distending one or both sides of the scrotum with ?uid. Treatment is by withdrawal of the ?uid using a sterile syringe and aspiration needle.

Hypogonadism Reduced activity of the testes or ovaries (male and female gonads). The result is impaired development of the secondary sexual characteristics (growth of the genitals, breast and adult hair distribution). The cause may be hereditary or the result of a disorder of the PITUITARY GLAND which produces GONADOTROPHINS that stimulate development of the testes and ovaries.

Varicocoele is distension of the veins of the spermatic cord, especially on the left side, the causes being similar to varicose veins elsewhere (see VEINS, DISEASES OF). The chief symptom is a painful dragging sensation in the testicle, especially after exertion. Wearing a support provides relief; rarely, an operation may be advisable. Low sperm-count may accompany a varicocele, in which case surgical removal may be advisable.

Orchitis or acute in?ammation may arise from CYSTITIS, stone in the bladder, and in?ammation in the urinary organs, especially GONORRHOEA. It may also follow MUMPS. Intense pain, swelling and redness occur; treatment consists of rest, support of the scrotum, analgesics as appropriate, and the administration of antibiotics if a de?nitive microorganism can be identi?ed. In some patients the condition may develop and form an ABSCESS.

Torsion or twisting of the spermatic cord is relatively common in adolescents. About half the cases occur in the early hours of the morning during sleep. Typically felt as pain of varying severity in the lower abdomen or scrotum, the testis becomes hard and swollen. Treatment consists of immediate undoing of the torsion by manipulation. If done within a few hours, no harm should ensue; however, this should be followed within six hours by surgical operation to ensure that the torsion has been relieved and to ?x the testes. Late surgical attention may result in ATROPHY of the testis.

Tuberculosis may occur in the testicle, especially when the bladder is already affected. Causing little pain, the infection is often far advanced before attracting attention. The condition generally responds well to treatment with a combination of antituberculous drugs (see also main entry for TUBERCULOSIS).

Tumours of the testes occur in around 600 males annually in the United Kingdom, and are the second most common form of malignant growth in young males. There are two types: SEMINOMA and TERATOMA. When adequately treated the survival rate for the former is 95 per cent, while that for the latter is 50 per cent.

Injuries A severe blow may lead to SHOCK and symptoms of collapse, usually relieved by rest in bed; however, a HAEMATOMA may develop.... testicle, diseases of

Alteratives. The blood is a fluid from which every variety of cell and tissue derives its special form of food for the repair of constant wastage resulting from functions they perform. When the blood becomes vitiated from lack of exercise, too little oxygen, debilitating personal habits and sophisticated foodstuffs the whole body suffers. The vital fluid then needs to be cleansed of its impurities. Nature’s blood purifiers are unique in the world of medicine, restoring biochemical balance and promoting healthy elimination.

Blood tonic. Decoction, tablets, tinctures or fluid extracts:– Echinacea 3; Burdock 2; Goldenseal 1. See also: ALTERATIVES. ... blood purifiers

Rare, but increasing in most countries. Three main types: teratomas, seminomas and lymphomas. The latter affect older men.

Symptoms. A hard usually painless mass in the scrotum can give rise to gynaecomastia – abnormal enlargement of the male breasts.

Of possible value. Alternatives: – Abundant herb teas – Cornsilk, Red Clover, Violet leaves.

Decoction. Echinacea 2; Kava Kava 1; Sarsaparilla 1. Mix. Half an ounce (15g) to 1 pint (500ml) water simmered gently 20 minutes. Cup thrice daily.

Formula. Sarsaparilla 2; Kava Kava l; Pulsatilla half; Thuja quarter. Mix. Dose: Powders: 500mg (two 00 capsules or one-third teaspoon). Liquid extracts: 1 teaspoon. Tinctures: 2 teaspoons. Thrice daily. Vinchristine.

Diet. See: DIET – CANCER. Researchers from Cambridge University found that an extra pint of milk a day during adolescence was associated with 2 and a half times increased risk of testicular cancer. (Journal of Epidemiology and Community Health, Oct. 1993)

Treatment by or in liaison with a general medical practitioner. ... cancer – testicles

See culture.... blood culture

The level of glucose in the blood. Abnormally high blood glucose (sometimes called sugar) levels are an indication of diabetes mellitus. (See also hyperglycaemia; hypoglycaemia.)... blood glucose

See blood film.... blood smear

The use of a person’s own blood, donated earlier, for blood transfusion. Autologous transfusion eliminates the slight but serious risk of contracting a serious infectious illness from contaminated blood. There is no risk of a transfusion reaction occurring as a result of incompatibility between donor and recipient blood. Up to 3.5 litres of blood can be removed and stored in several sessions at least 4 days apart and up to 3 days before planned surgery. Blood may be salvaged during surgery, filtered and returned to the circulation, reducing the need for transfusion of donated blood.... blood transfusion, autologous

A general term given to arteries, veins, and capillaries (see circulatory system).... blood vessels

One of a group of tests used to assess the function of the heart in people who experience chest pain, breathlessness, or palpitations during exercise. The test establishes whether the patient has coronary artery disease. An ECG machine records the patterns of the heart’s electrical activity while the heart is stressed. This is usually achieved by the patient exercising on a treadmill or cycling. Specific changes in the electrical pattern as exercise levels increase indicate angina. Cardiac stress testing may be used in conjunction with radionuclide scanning to identify damaged areas of heart muscle.... cardiac stress test

Cells, also called blood corpuscles, present in blood for most or part of their lifespan. They include red blood cells, which make up about 45 per cent by volume of normal blood, white blood cells, and platelets. Blood cells are made in the bone marrow by a series of divisions from stem cells.

Red blood cells (also known as RBCs, red blood corpuscles, or erythrocytes) transport oxygen from the lungs to the tissues (see respiration). Each is packed with haemoglobin, enzymes, minerals, and sugars. Abnormalities can occur in the rate at which RBCs are either produced or destroyed, in their numbers, and in their shape, size, and haemoglobin content, causing forms of

anaemia and polycythaemia (see blood, disorders of).

White blood cells (also called WBCs, white blood corpuscles, or leukocytes) protect the body against infection and fight infection when it occurs. The 3 main types of are granulocytes (also called polymorphonuclear leukocytes), monocytes, and lymphocytes. Granulocytes are further classified as neutrophils, eosinophils, or basophils, and each type of granulocyte has a role in either fighting infection or in inflammatory or allergic reactions. Monocytes and lymphocytes also play an important part in the immune system. Lymphocytes are usually formed in the lymph nodes. One type, a T-lymphocyte, is responsible for the delayed hypersensitivity reactions

White (see allergy) and Red blood blood cell is also involved in cell (neutrophil) protection against cancer. T-lymphocytes manufacture chemicals, known as lymphokines, which affect the function of other cells. In addition, the T-cells moderate the activity of B-lymphocytes, which form the antibodies that can prevent a second attack of certain infectious diseases. Platelets (also known as thrombocytes), are the smallest blood cells and are important in blood clotting.

The numbers, shapes, and appearance of the various types of blood cell are of great value in the diagnosis of disease (see blood count; blood film).... blood cells

Disorders resulting from abnormalities in any of the components of blood or from infection. Disorders include types of anaemia, polycythaemia, bleeding disorders, and unwanted clot formation (thrombosis), hypoalbuminaemia (albumin deficiency) and agammaglobulinaemia (deficiency of gamma-globulin). Blood disorders such as sickle cell anaemia, thalassaemia, and haemophilia are inherited. Bone marrow cancers that affect production of blood components include leukaemia, polycythaemia vera, and multiple myeloma. Blood poisoning is usually due to septicaemia or a toxin such as carbon monoxide. Some drugs can cause blood abnormalities as a side effect. (See also anaemia, haemolytic; anaemia, iron-deficiency; anaemia, megaloblastic; malaria; hyperbilirubinaemia.)... blood, disorders of

The process of giving blood for use in blood transfusion.

Donated blood is tested for a range of infectious agents such as hepatitis B and hepatitis C and antibodies to HIV. After being classified into blood groups, the blood is stored in a blood bank, either whole or separated into its different components (see blood products). Apheresis is a type of blood donation in which only a specific blood component, such as plasma, platelets, or white cells, is withdrawn from the donor. blood film A test that involves smearing a drop of blood on to a glass slide for examination under a microscope. The blood film is stained with dyes to make the blood cells show up clearly.

The test allows the shape and appearance of blood cells to be checked for any abnormality, such as the sickleshaped red blood cells characteristic of sickle cell anaemia.

The relative proportions of the different types of white blood cells can also be counted.

This examination, called a differential white cell count, may be helpful in diagnosing infection or leukaemia.

Blood films are also used in diagnosing infections, such as malaria, in which the parasites can be seen inside the red blood cells.

Blood films are usually carried out together with a full blood count.... blood donation

A test to detect cervical dysplasia (abnormal changes in the cells of the cervix) that could develop into cervical cancer (see cervix, cancer of). A smear test also detects viral infections of the cervix, such as herpes simplex and papilloma (see warts, genital). The test should be carried out 6 months after a woman starts to have sexual intercourse, with a repeat test 6–12 months later, and then every 3 years.

A sample of cells is taken from the surface of the cervix using a spatula and examined under a microscope.

If cells appear normal, nothing further needs to be done.

If cells show dysplasia, further investigations may be required.... cervical smear test

The main mechanism by which blood clots are formed, involving a complex series of reactions in the blood plasma (see blood clotting).... coagulation, blood

A laboratory blood test commonly used in the diagnosis of infectious diseases. stands for enzyme-linked immunosorbent assay.

(See also immunoassay.)... elisa test

Donated blood that is separated into its various components: red cells, white cells, platelets, and plasma (see blood donation). Each blood product has a specific lifespan and use in blood transfusion. Packed red cells (blood with most of the plasma removed) are used to treat patients with some forms of chronic anaemia and babies with haemolytic disease of the newborn. Washed red cells (with white blood cells and/or plasma proteins removed) are used when a person needs repeated transfusions because there is less risk of an allergy to any of the blood components developing.

Platelets may be given in transfusions for people with blood-clotting disorders. Patients who have life-threatening infections may be treated with granulocytes, a type of white blood cell. Fresh frozen plasma is used to correct many types of bleeding disorder because it contains all the clotting factors. Albumin, prepared from the plasma of whole blood, is used mainly to treat shock resulting from severe blood loss until compatible whole blood becomes available. Purified albumin preparations are used to treat nephrotic syndrome and chronic liver disease.

Concentrates of blood clotting factors and are used in the treatment of haemophilia and Christmas disease.

Immunoglobulins (also called antibodies), which are extracted from blood plasma, can be given by injection (see immunoglobulin injection) to protect people who are unable to produce their own antibodies or have already been exposed to an infectious agent, or to provide short-term protection against hepatitis A.

Immunoglobulins are given in large doses to treat certain autoimmune disorders.... blood products

Analysis of a sample of blood to give information on its cells and proteins and any of the chemicals, antigens, antibodies, and gases that it carries. Such tests can be used to check on the health of major organs, as well as on respiratory function, hormonal balance, the immune system, and metabolism. Blood tests may look at numbers, shape, size, and appearance of blood cells and assess the function of clotting factors. The most important tests are blood count and blood group tests if transfusion is needed. Biochemical tests measure chemicals in the blood (see acid–base balance; kidney function tests; liver function tests). Microbiological tests (see immunoassay) look for microorganisms that are in the blood, as

in septicaemia. Microbiology also looks for antibodies in the blood, which may confirm immunity to an infection. blood transfusion The infusion of large volumes of blood or blood products directly into the bloodstream to remedy severe blood loss or to correct chronic anaemia. In an exchange transfusion, nearly all of the recipient’s blood is replaced by donor blood. Before a transfusion, a sample of the recipient’s blood is taken to identify the blood groups, and it is matched with suitable donor blood. The donor blood is transfused into an arm vein through a plastic cannula. Usually, each unit (about 500 ml) of blood is given over 1–4 hours; in an emergency, 500 ml may be given in a couple of minutes. The blood pressure, temperature, and pulse are monitored during the procedure.

If mismatched blood is accidentally introduced into the circulation, antibodies in the recipient’s blood may cause donor cells to burst, leading to shock or kidney failure. Less severe reactions can produce fever, chills, or a rash. Reactions can also occur as a result of an allergy to transfused blood components. All

blood used for transfusion is carefully screened for a number of infectious agents, including HIV (the AIDS virus) and hepatitis B and hepatitis C.

In elderly or severely anaemic patients, transfusion can overload the circulation, leading to heart failure.

In patients with chronic anaemia who need regular transfusion over many years, excess iron may accumulate (haemosiderosis) and damage organs such as the heart, liver, and pancreas.

Treatment with desferrioxamine to remove excess iron may be needed.... blood tests

A symptom, medically known as haemoptysis, that is caused by rupture of a blood vessel in the air-ways, lungs, nose, or throat. The coughed-up blood may appear as brightred or rusty-brown streaks, clots in the sputum, a pinkish froth, or, more rarely, blood alone. In all cases, medical assessment is needed. Many disorders can cause haemoptysis. The most common are infections, such as pneumonia or bronchitis; and congestion in and rupture of blood vessels in the lungs due to heart failure, mitral stenosis, or pulmonary embolism. A cancerous tumour can also produce haemoptysis by eroding the wall of a blood vessel.

Investigations into coughing up blood include chest X-ray, and, in some cases, bronchoscopy. In about a 3rd of cases, no underlying cause is found. Treatment depends on the cause.... coughing up blood

See faeces, abnormal; rectal bleeding.... faeces, blood in the

A test for meningitis that involves pressing a clear glass against a rash. If the rash remains visible, it may be a form of purpura, which sometimes occurs in meningitis.... glass test

An outdated psychological test in which the subject was asked to interpret the appearance of a number of ink blots. The most widely used example was the Rorschach test.... ink-blot test

Tests performed to investigate kidney disorders.

Urinalysis is a simple test in which a urine sample is examined under a microscope for blood cells, pus cells, and casts (cells and mucous material that accumulate in the tubules of the kidneys and pass into the urine).

Urine may be tested for substances, such as proteins, that leak into the urine when the kidneys are damaged.

Kidney function can be assessed by measuring the concentration in the blood of substances, such as urea and creatinine, that the kidneys normally excrete.

Kidney function may also be assessed by kidney imaging techniques.... kidney function tests

Tests of blood chemistry that can detect changes in the way the liver is making new substances and breaking down and/or excreting old ones.

The tests can also show whether liver cells are healthy or being damaged.... liver function tests

See pulmonary function tests.... lung function tests

A series of exercises designed to determine an individual’s level of fitness, primarily cardiovascular fitness and muscle performance. Fitness testing is often carried out before a person starts an exercise programme to evaluate its safety and suitability or to monitor progress thereafter.

A physical examination is usually performed, including measurement of body fat, height, and weight. Blood and urine tests may be done, including an analysis of blood cholesterol. The performance of the heart is measured by taking the pulse before, during, and after aerobic exercise. Another test involves measuring a person’s overall performance in a standard exercise. (See also aerobics; exercise.)... fitness testing

Tests carried out to assess hearing. Hearing tests are performed as part of a routine assessment of child development and when hearing impairment is suspected. The tests are sometimes included in a general medical examination. Hearing tests may also be used to identify the cause of tinnitus or dizziness.

An audiometer (an electrical instrument) is used to test an individual’s ability to hear sounds at different frequencies and volumes. The lowest level at which a person can hear and repeat words (the speech reception threshold) is tested, as is the ability to hear words clearly (speech discrimination). The type of hearing loss (see deafness) is determined by holding a tuning fork to different parts of the ear.... hearing tests

Tests designed to provide an estimate of a person’s mental abilities. The most widely used are Wechsler tests of which there are 2 basic types: the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children (WISC). Each is divided into verbal (concerned with language skills) and performance sections, including measures of constructional ability and visual-spatial and perceptual ability (interpretation of shapes). Other tests include the Stanford–Binet test, which is used mainly as a measure of scholastic ability.

In most intelligence tests, scoring is based on mental age (MA) in relation to chronological age (CA). The intelligence quotient (IQ) is MA divided by CA, multiplied by 100. The tests are devised to ensure that 3 in 4 people have an IQ between 80 and 120. They are standardized so that the score indicates the same relative ability at different age levels.

Intelligence tests may be used to assess school or job aptitude. However, they have been criticized for their alleged bias regarding gender and race.... intelligence tests

The presence in the faeces of blood that cannot be seen by the naked eye, but can be detected by chemical tests. Such tests are widely used in screening for cancer of the colon (see colon, cancer of). Faecal occult blood may also be a sign of a gastrointestinal disorder such as oesophagitis, gastritis, or stomach cancer; cancer of the intestine (see intestine, cancer of); rectal cancer (see rectum, cancer of); diverticular disease; polyps in the colon; ulcerative colitis; or irritation of the stomach or intestine by drugs such as aspirin. (See also rectal bleeding.)... occult blood, faecal

The use of blood tests to help decide whether a man is the father of a child.

Blood samples are taken from the child, from the suspected father, and sometimes from the mother.

The samples are tested for blood groups, histocompatibility antigens, and similarities in DNA.

Genetic fingerprinting provides the most decisive result.... paternity testing

Questionnaires designed to define various personality traits or types. Tests may be designed to detect psychiatric symptoms, underlying personality traits, how outgoing or reserved a person is, and predisposition to developing neurotic illness.... personality tests

See Guthrie test.... pku test

See pulmonary function tests.... respiratory function tests

A usually harmless condition in which a small amount of blood is present in the semen.

Occasionally, there is an underlying cause (such as an infection or, very rarely, cancer) that requires treatment.

Blood in the semen may also occur after a prostate biopsy.... semen, blood in the

Procedures for determining the body’s reaction to various substances by injecting a small quantity of the substance under the skin or by applying it to the skin (usually on patches).

Patch tests are used in the diagnosis of contact allergic dermatitis.

They can also be used to test immunity to certain infectious diseases (such as in the tuberculin test).... skin tests

A type of intelligence test.... stanford–binet test

A rare, cancerous tumour of the testis. Testicular cancer is most common in young to middle-aged men, and the risk increases in individuals with a history of undescended testis (see testis, undescended). The most common types of testicular cancer are seminomas, which are made up of only 1 type of cell, and teratomas. The cancer usually appears as a firm, painless swelling of 1 testis. There may also be pain and inflammation. Biopsy, followed by orchidectomy, is the usual treatment, and may be combined with chemotherapy. The tumours usually respond well to treatment.... testis, cancer of

A testis that is absent from the scrotum because it has descended into an abnormal position, usually in the groin or at the base of the penis. The condition is most often discovered soon after birth during a routine physical examination. It is treated by orchidopexy. (See also testis, undescended.) ... testis, ectopic

Pain in a testis may be caused by mild injury, a tear in the wall of the testis due to a direct blow, orchitis, epididymo-orchitis, and torsion of the testis (see testis, torsion of). Sometimes, no cause is found and the pain disappears without treatment. If the wall of the testis is torn, an operation to repair it may be needed. ... testis, pain in the

Swelling of the testis or the surrounding tissues in the scrotum. Harmless and painless swellings include epididymal cysts, hydroceles, varicoceles, and spermatoceles. Cancer of the testis (see testis, cancer of) is rare but may be a cause of painless swelling. Swelling that is painful may be caused by a direct blow, torsion of the testis (see testis, torsion of), orchitis, epididymoorchitis, or, in very rare cases, cancer of the testis. Any swelling of the testes should be assessed promptly by a doctor.... testis, swollen

Twisting of the spermatic cord that causes severe pain and swelling of the testis. The pain develops rapidly and is sometimes accompanied by abdominal pain and nausea. The testis becomes swollen and very tender, and the skin of the scrotum becomes discoloured. Unless the torsion is treated within a few hours, permanent damage to the testis results. The condition is most common around puberty. It is more likely to occur if the testis is unusually mobile within the scrotum.

Diagnosis is by physical examination.

Surgery is performed to untwist the testis and anchor it in the scrotum with small stitches to prevent recurrence.

If irreversible damage has occurred, orchidectomy is performed.

In either case, the other testis is anchored to the scrotum to prevent torsion on that side.

With prompt treatment, recovery of the testis is complete.... testis, torsion of

A testis that has failed to descend from the abdomen to the scrotum. The condition usually affects only 1 testis and occurs in about 1 per cent of full-term and 10 per cent of premature male babies. An undescended testis often descends within months of birth but rarely descends after this time. An undescended testis does not develop normally, is incapable of normal sperm production, and is at increased risk of developing testicular cancer (see testis, cancer of). If both testes are undescended, infertility results.

A diagnosis is made during a physical examination after birth or later in infancy.

Treatment is by orchidopexy, which usually reduces the risk of later infertility or testicular cancer (see testis, cancer of).

A poorly developed undescended testis may be removed if the other is normal.... testis, undescended

Tests may be performed to investigate the cause of symptoms and establish a diagnosis, to monitor the course of a disease, or to assess response to treatment. A medical testing programme carried out on apparently healthy people to find disease at an early stage is known as screening.

The accuracy of a test is based on its sensitivity (ability to correctly identify diseased subjects), specificity (ability to correctly identify healthy subjects), and predictive value.

The predictive value is determined by a mathematical formula that involves the number of accurate test results and the total number of tests performed.

The best tests have both high specificity and high sensitivity, and therefore high predictive value.... tests, medical

A group of blood tests used to evaluate the function of the thyroid gland and to detect or confirm any thyroid disorder. The thyroid hormones T3 and T4 are measured, as well as thyroid-stimulating hormone (TSH), the pituitary gland hormone that stimulates the thyroid gland.... thyroid-function tests

Skin tests used to determine whether or not a person has been exposed to the bacterium that causes tuberculosis. Tuberculin tests are carried out for diagnosis of tuberculosis, and before BCG vaccination. A small amount of tuberculin (purified protein from the bacteria) is injected into the skin. A few days later, the skin reaction, if any, is noted. A reaction indicates previous exposure.... tuberculin tests

Hearing tests carried out to diagnose conductive deafness. In the Weber test, a vibrating tuning fork is held against the forehead. If there is conductive hearing loss, the sound seems louder in the affected ear. In the Rinne test, a vibrating tuning fork is held first near the ear, and then against the bone behind it. If it sounds louder when held against the bone, there is conductive hearing loss.... tuning fork tests

See urinalysis.... urine tests

a test for the presence of sugar in urine or other liquids. A few drops of the test solution are added to Benedict’s solution, prepared from sodium or potassium citrate, sodium carbonate, and copper sulphate. The mixture is boiled and shaken for about two minutes, then left to cool. The presence of up to 2% glucose is indicated by the formation of a reddish, yellowish, or greenish precipitate, the highest levels corresponding to the red coloration, the lowest (about 0.05%) to the green. [S. R. Benedict (1884–1936), US surgeon]... benedict’s test

A symptom of bleeding from within the digestive tract. Vomiting blood may be caused by a tear in the lower oesophagus (see Mallory–Weiss syndrome), bleeding from oesophageal varices, erosive gastritis, peptic ulcer, or, rarely, stomach cancer. Blood can also be vomited if it is swallowed during a nosebleed. Vomited blood may be dark red, brown, black, or may resemble coffee grounds. Vomiting of blood is often accompanied by the passing of black, tarry faeces.

The cause of vomiting blood is investigated by endoscopy of the oesophagus and stomach, or by barium X-ray examinations. If blood loss is severe, blood transfusion, and possibly surgery to stop the bleeding, may be required.... vomiting blood

(blood corpuscle) any of the cells that are present in the blood in health or disease. The cells may be subclassified into three major categories, namely red cells (*erythrocytes); white cells (*leucocytes), which include granulocytes, lymphocytes, and monocytes; and *platelets (see illustration). The blood cells account for approximately 40% of the total volume of the blood in health; red cells comprise the vast majority.... blood cell

(blood clotting) the process whereby blood is converted from a liquid to a solid state. The process may be initiated by contact of blood with a foreign surface (intrinsic system) or with damaged tissue (extrinsic system). These systems involve the interaction of a variety of substances (*coagulation factors) and lead to the production of the enzyme thrombin, which converts the soluble blood protein *fibrinogen to the insoluble protein *fibrin, forming the blood clot. Finally, fibrin is broken down by the action of *plasmin. Anticoagulants and tissue plasminogen activators act by inhibiting or activating various pathways in this cascade (see illustration). Blood coagulation is an essential mechanism for the arrest of bleeding (*haemostasis). See also platelet activation.... blood coagulation

any one of the many types into which a person’s blood may be classified, based on the presence or absence of certain inherited antigens on the surface of the red blood cells. Blood of one group contains antibodies in the serum that react against the cells of other groups.

There are more than 30 blood group systems, one of the most important of which is the ABO system. This system is based on the presence or absence of antigens A and B: blood of groups A and B contains antigens A and B, respectively; group AB contains both antigens and group O neither. Blood of group A contains antibodies to antigen B; group B blood contains anti-A antibodies or *isoagglutinins; group AB has neither antibody and group O has both. A person whose blood contains either (or both) of these antibodies cannot receive a transfusion of blood containing the corresponding antigens. The table illustrates which blood groups can be used in transfusion for each of the four groups.

Blood group... blood group

Blood group of people donor can receive blood from... donor’s blood group

... blood plasma see plasma.

see serum.... blood serum

where clinical *negligence is claimed, tests used to determine the standard of care owed by professionals to those whom they serve, e.g. the standards of care provided to patients by doctors. The 1957 case of Bolam v Friern Hospital Management Committee established that if a doctor acts in accordance with a responsible body of medical opinion, he or she will not be negligent. In 1997 this standard of care test was amended by the case of Bolitho v City and Hackney Health Authority, which requires the doctor’s behaviour to satisfy the judgment not only of responsible medical opinion but also of a court’s own independent logical analysis.... bolam and bolitho tests

(in statistics) a test to determine if the difference between two groups of observations is statistically significant (see significance), used in controlled trials and other studies. It measures the differences between theoretical and observed values and identifies whether or not *variables are related.... chi-square test

a test used to detect a squint. The observer looks at a target object, one eye at a time being covered. If the uncovered eye deviates to focus on the target, then a squint is confirmed. The movement can be up, down, sideways, or a combination, depending on the type of squint (see strabismus).... cover test

a screening tool for young people under the age of 21 to identify alcohol and drug use. The first part consists of three questions about drug or alcohol use over the past year. Participants giving positive answers to two or more questions proceed to the second part (from which the name derives), which contains six questions with the key words car, relax, alone, family/friends, forget, trouble, used to assess the need for further input.... crafft screening test

a hearing test used for screening infants between the ages of six and ten months. The infant is placed on its carer’s knee, one examiner sits in front of the infant and gains its attention, and a second examiner is situated just behind the infant. At a given moment the first examiner becomes very still and the second examiner makes a sound at the level of the infant’s ear to one side or the other. If the infant can hear it turns in the direction of the sound. The sounds made should be of different pitches and a given loudness.... distraction test

(DSTs) tests based on the principle that appropriate doses of *dexamethasone can suppress the output of cortisol from the adrenal glands in the normal state and that this ability is reduced or lost in *Cushing’s syndrome. In the overnight DST 1 mg of dexamethasone is administered at midnight and the serum cortisol level is measured at 9.00 am the next morning. Failure to suppress cortisol output may indicate Cushing’s syndrome but also occurs in patients with obesity and depressive illness. In the low-dose DST (0.5 mg dexamethasone every 6 hours for 48 hours), cortisol suppression occurs in patients with obesity and depression but not in those with Cushing’s syndrome. In the high-dose DST (2 mg dexamethasone every 6 hours for 48 hours), cortisol is suppressed in patients with Cushing’s disease (in which excess amounts of ACTH are secreted by the pituitary gland) but not in those with Cushing’s syndrome due to other causes. Although the low- and high-dose tests are unreliable, all three tests should be performed to aid the diagnosis of Cushing’s syndrome.... dexamethasone suppression tests

(Hallpike test) a test for *benign paroxysmal positional vertigo (BPPV), performed with the patient first sitting upright on an examination couch and then lying supine with the head and neck extended beyond the edge of the couch. The patient’s head is rotated to the left (or right) and supported by the examiner while the patient assumes the supine position and keeps his or her eyes focused on the examiner’s eyes. The test is then repeated with the other ear facing down. In patients with BPPV, after a short delay rotatory *nystagmus is seen, in association with severe vertigo and nausea, which gradually abates. The effect diminishes with repeated manoeuvres. In conditions affecting the cerebellum or brainstem, the nystagmus occurs immediately, in any direction, and does not diminish, and patients do not feel especially nauseated. [M. R. Dix and C. S. Hallpike (20th century), British otologists]... dix–hallpike test

(FOBT) a noninvasive test used to identify microscopic blood (see occult) in faeces. It is widely used as a screening test for colorectal cancer.... faecal occult blood test

a test for detecting the presence of sugar in urine, which has now been replaced by better and easier methods. [H. von Fehling (1812–85), German chemist]... fehling’s test

a test for folate or vitamin B12 deficiency. A dose of the amino acid histidine, which requires the presence of folate or vitamin B12 for its complete breakdown, is given by mouth. In the absence of these vitamins, formiminoglutamic acid (figlu) – an intermediate product in histidine metabolism – accumulates and can be detected in the urine.... figlu test

a test for *ataxia or cerebral lesions. Using the index finger, the patient alternately touches his or her nose and then the examiner’s finger, which is shifted to a new position for each of the patient’s movements. The test is positive if the patient misses a target or develops a tremor as the target is approached (intention tremor).... finger–nose test

(FPL test) a test used to evaluate the *visual acuity of infants and young children by observing whether the child looks at a blank screen or one with stripes, the spatial frequency of which can be changed.... forced preferential looking test

see forced preferential looking test.... fpl test

a rarely used diagnostic test for the sexually transmitted disease *lymphogranuloma venereum. A small quantity of the virus, inactivated by heat, is injected into the patient’s skin. If the disease is present a small red swelling appears at the site of injection within 48 hours. [W. S. Frei (1885–1943), German dermatologist]... frei test

a test for *phaeochromocytomas not displaying typically high levels of plasma *catecholamines. An intravenous bolus of *glucagon is administered and the test is positive when there is a threefold increase in plasma catecholamine levels with a consequent rise in blood pressure. The test is now very rarely used due to safer and more sensitive screening tests, combined with modern tumour imaging techniques.... glucagon stimulation test

(heel-prick blood test) a blood test performed on all newborn babies at the end of the first week of life. The blood is obtained by pricking the heel of the baby. The test can detect several *inborn errors of metabolism (including *phenylketonuria) and *hypothyroidism; it can also be used for detecting *cystic fibrosis, although this is not routinely offered. [R. Guthrie (1916–95), US paediatrician]... guthrie test

see Dix–Hallpike test.... hallpike test

see Guthrie test.... heel-prick blood test

a test for the presence of protein (albumin) in the urine. A quantity of urine is carefully poured onto the same quantity of pure nitric acid in a test tube. A white ring forms at the junction of the liquids if albumin is present. However, a similar result may be obtained if the urine contains certain drugs or is very concentrated. A dark brown ring indicates the presence of an abnormally high level of potassium indoxyl sulphate in the urine (see indicanuria). [J. F. Heller (1813–71), Austrian pathologist]... heller’s test

an important but potentially dangerous test of anterior pituitary function involving the deliberate induction of a hypoglycaemic episode with injected insulin and the subsequent measurement of plasma cortisol and growth hormone at regular intervals over the next three hours. The stress of the hypoglycaemia should induce a rise in the levels of these hormones unless the anterior pituitary or the adrenal glands are diseased. The test can induce epileptic seizures or angina in those with a predisposition and should not be performed in susceptible individuals. It is often combined with the thyrotrophin-releasing hormone (TRH) test and the gonadotrophin-releasing hormone (GnRH) test in what is known as the triple test (or dynamic pituitary function test).... insulin stress test

a card with text printed in type of different sizes, used for testing acuity of near vision. [E. R. Jaeger von Jastthal (1818–84), Austrian ophthalmologist]... jaeger test types

a test to detect and measure fetal red blood cells in the maternal circulation of Rh-negative women who have *antepartum haemorrhage or have previously had a Rh-positive baby. It is used to calculate the correct dose of *anti-D immunoglobulin that will prevent *haemolytic disease of the newborn.... kleihauer–betke test

a test of the ability of the pituitary to secrete growth hormone, in which levodopa is administered by mouth and plasma levels of growth hormone are subsequently measured (they should peak within the following hour). It is a safer alternative to the *insulin stress test but does not give information on cortisol production, which is usually more clinically important to know.... levodopa test

see significance.... mann–whitney u test

a hearing test used in preschool children in which the child must discriminate between similar speech sounds. The test consists of 14 toys that are paired because their names sound similar; for example, tree and key, plane and plate. Having first identified all the objects, the child is then asked in a quiet voice to indicate a particular toy (e.g. Can you find the key?).... mccormick toy test

a simple noninvasive procedure that enables the detection of *carriers for single gene defects, e.g. *cystic fibrosis. Epithelial cells from the buccal cavity are obtained from a saline mouthwash: from these it is possible to isolate DNA, which is amplified by the *polymerase chain reaction to enable gene analysis.... mouthwash test

(NHSBT) a *special health authority established in 2005 to provide a safe and reliable supply of blood, organs, stem cell services, and diagnostics to hospitals. NHSBT also provides specialist therapeutic apheresis services, which remove or replace a single component of blood (e.g. malignant white cells or low-density lipoprotein), at six sites in England.

NHS Blood and Transplant website... nhs blood and transplant

a three-question tool designed to uncover any connection between an individual’s attendance at an A & E department and alcohol-related problems, thereby creating the potential for intervention and referral.... paddington alcohol test

see significance.... parametric test

a test used in the investigation of infertility. A specimen of cervical mucus, taken 6–24 hours after coitus, is examined under a microscope. The appearance of 10 or more progressively motile spermatozoa per high-power field in the specimen indicates that there is no abnormal reaction between spermatozoa and mucus. The test should be undertaken in the postovulatory phase of the menstrual cycle.... postcoital test

(in psychology) a way of measuring aspects of personality, in which the subject is asked to talk freely about ambiguous objects. His responses are then analysed. Examples are the *Rorschach test and the Thematic Apperception Test (in which the subject invents stories about a set of pictures).... projective test

a part of the routine *lumbar puncture procedure. It is used to determine whether or not the flow of cerebrospinal fluid is blocked in the spinal canal. [H. H. G. Queckenstedt (1876–1918), German physician]... queckenstedt test

tests for assessing the function of the kidneys. These include measurements of the specific gravity of urine, creatinine *clearance time, and blood urea levels; intravenous urography; and renal angiography.... renal function tests

a test to determine whether *deafness is conductive or sensorineural. A vibrating tuning fork is held first in the air, close to the ear, and then with its base placed on the bone (mastoid process) behind the ear. If the sound conducted by air is heard louder than the sound conducted by bone the test is positive and the deafness sensorineural; a negative result, when the sound conducted by bone is heard louder, indicates conductive deafness. [H. A. Rinne (1819–68), German otologist]... rinne’s test

any of several methods used to demonstrate whether or not a woman is pregnant. Most pregnancy tests are based on the detection of a hormone, *human chorionic gonadotrophin (hCG), in the urine. The sample of urine is mixed with serum containing antibodies to hCG and marker particles (sheep red cells or latex particles) coated with hCG. In the absence of pregnancy, the antibodies will cause *agglutination of the marker particles. If the urine is from a pregnant woman, the antibodies will be absorbed and no agglutination will occur. These tests may be positive for pregnancy as early as 30 days after the date of the last normal period and are 98% accurate. Newer tests using *monoclonal antibodies (beta hCG) are more easily interpreted. When carried out on serum rather than urine, these tests give even earlier positive results.... pregnancy test

a method of testing urine for the presence of acetone or acetoacetic acid: a sign of *diabetes mellitus. Strong ammonia is added to a sample of urine saturated with ammonium sulphate crystals and containing a small quantity of sodium nitroprusside. A purple colour confirms the presence of acetone or acetoacetic acid. [A. C. H. Rothera (1880–1915), Australian biochemist]... rothera’s test

a test to determine whether a person is susceptible to diphtheria. A small quantity of diphtheria toxin is injected under the skin; a patch of reddening and swelling shows that the person has no immunity and – if at particular risk – should be immunized. With safer *toxoids, this test is no longer necessary. [B. Schick (1877–1967), US paediatrician]... schick test

a test used to assess a patient’s capacity to absorb vitamin B12 from the bowel. Radioactive vitamin B12 is given by mouth and urine collected for 24 hours. A normal individual will excrete at least 10% of the original dose over this period; a patient with *pernicious anaemia will excrete less than 5%. [R. F. Schilling (1919), US physician]... schilling test

a test for detecting visual impairment in children who are too young to be able to read the *Snellen chart. A series of cards, each marked with a single letter of a specific size, are held up at a distance of 6 metres from the child being tested. The child is provided with an identification card containing a selection of letters and is asked to point to the letter that is the same as the one on the card in the distance. The test is suitable for children between the ages of two and seven.... sheridan–gardiner test

an investigation to seek evidence of cardiac *ischaemia. The heart is stressed by exercise or by the administration of an intravenous drug that increases heart rate (i.e. mimicked exercise). Ischaemia may then be detected by electrocardiography (stress ECG or exercise ECG), *echocardiography (showing the development of impaired function in areas of heart muscle that are ischaemic), *myocardial perfusion scan, or cardiac MRI.... stress test

see significance. [Pseudonym of W. S. Gosset (1876–1937), British statistician]... student’s t test

Standard Tests for Young Children and Retardates: tests to detect visual problems in children between the ages of six months and five years. They consist of a series of standardized balls, toys, or letters. The tests were developed by the paediatrician Mary Sheridan.... stycar tests

tests used to assess the ability of the adrenal cortex to produce cortisol. Serum cortisol is measured before and then 30 minutes (or 5 hours) after an intramuscular injection of 250 ?g (or 1 mg) tetracosactide (Synacthen), an analogue of *ACTH. The adrenal glands are considered to be inadequate if there is a low baseline concentration of cortisol or the rise is less than a certain predefined amount.... synacthen tests

(Trendelenburg’s sign) a test for detecting dysfunction of the hip joint. Normally when a leg is lifted off the ground, the pelvis on the same side is raised by the hip abductor muscles on the other side. If these muscles cannot raise the pelvis against body weight, the pelvis will tilt downwards and the test is positive, indicating arthritis, paralysis of the muscles due to superior gluteal nerve injury, or other hip pathology (e.g. congenital hip dislocation). [F. Trendelenburg]... trendelenburg’s test

1. (in *prenatal screening) a blood test that can be performed between the 15th and 20th weeks of pregnancy but has largely been replaced by combined first-trimester *PAPP-A screening and *nuchal translucency scanning. Levels of *alpha-fetoprotein (AFP), *unconjugated oestriol (uE3), and *human chorionic gonadotrophin (hCG) in the serum are computed with maternal age to determine the statistical likelihood of the fetus being affected by Down’s syndrome or spina bifida. The double test is similar but omits measurement of uE3. 2. see insulin stress test.... triple test

haemopoietic *stem cells collected from umbilical cord blood donated at birth, which can be stored indefinitely and used if a sibling or any other blood-compatible baby develops an illness (such as leukaemia) that could only be treated by cord-blood stem-cell transplantation. This facility is now available in the UK and the USA.... umbilical cord blood banked stem cells

(VEMP) a test used to measure the response of the *saccule. It is used in the diagnosis of *superior canal dehiscence syndrome, *Ménière’s disease, and other disorders of the inner ear.... vestibular evoked myogenic potential test

a test for *diabetes insipidus in which fluid and food intake is withheld completely for up to 24 hours, with regular measurement of plasma and urinary *osmolality and body weight. Normally (and in a person with psychogenic *polydipsia) the output of *vasopressin will be increased in order to concentrate the urine as the plasma osmolality rises; correspondingly, the urine osmolality also rises and its volume diminishes. In a patient with diabetes insipidus, however, the urine osmolality will remain low and of high volume while the patient steadily dehydrates. The test must be abandoned if the patient loses 3% of body weight.... water-deprivation test

a hearing test in which a vibrating tuning fork is placed at the midpoint of the forehead. A normal individual hears it equally in both ears, but if one ear is affected by conductive *deafness the sound appears louder in the affected ear. If one ear has a sensorineural deafness the sound appears louder in the unaffected ear. [F. E. Weber (1832–91), German otologist]... weber’s test

a direct percutaneous renal infusion test to investigate possible obstruction of the ureter or kidney. It detects subtle obstructions that cannot be detected by imaging. [R. Whitaker (20th century), British urologist]... whitaker’s test