impedence test
| metyrapone test | <endocrinology, investigation> This test measures the ability of the pituitary gland to secrete ACTH in response to a low serum cortisol level. Under normal conditions a low serum cortisol level should stimulate the pituitary to produce ACTH, which stimulates the adrenal glands to produce more cortisol. This test is performed by injecting metyrapone into the bloodstream and then measuring cortisol levels over a period of time. Metyrapone is a substance which inhibits an enzyme (steroid 11-beta hydroxylase) involved in the synthesis of cortisol. This enzyme normally converts 11-deoxycortisol to cortisol. When the enzyme is inhibited, 11-deoxycortisol levels will increase in the blood and urine and cortisol levels will go down. This test is useful in differentiating the different forms of Cushing's syndrome: adrenal hyperplasia versus primary adrenal tumour. Those with an adrenal tumour (or carcinoma) generally have no response to metyrapone injection, since the dose is insufficient to inhibit cortisol synthesis. (27 Sep 1997) |
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| Ropes test | A test that reflects the polymerization of synovial fluid hyaluronate; a few drops of synovial fluid added to acetic acid form a clot; poor clot formation occurs in a variety of inflammatory conditions including septic arthritis, gouty arthritis, and rheumatoid arthritis. Synonym: Ropes test. (05 Mar 2000) |
| rorschach test | A projective test used to evaluate a broad range of personality variables including pathology of thought and perception. The subject's responses to inkblot prints are scored along with subjective interpretation by the test administrator. (12 Dec 1998) |
| MHA-TP test | A microtiter version of the Treponema pallidum haemagglutination test. Synonym: MHA-TP test. (05 Mar 2000) |
| rose bengal radioactive test | A test of liver function used as a means of measuring hepatic blood flow and for scintillation scanning of the liver to determine size and contour of the liver, or the presence of space-occupying masses in the liver. (05 Mar 2000) |
| Rosenbach-Gmelin test | A test for bile in the urine or other body fluid; nitric acid, with a little nitrous acid, is cautiously added to a few milliliters of the material to be tested; if bile (bilirubin) is present, it is oxidised to varying degrees, thereby resulting in disklike zones that are (from the interface outward) yellow, red, violet, blue, and green; development of green and violet layers is essential to the validity of the test. Synonym: Rosenbach-Gmelin test. (05 Mar 2000) |
| Rosenbach's test | A test for bile in the urine; the suspected urine is passed several times through the same filter paper, which is then dried and touched with a drop of slightly fuming nitric acid; the presence of bile is indicated by the resulting play of colours characteristic of the bile pigments (a yellow spot surrounded by rings of red, violet, blue, and green). (05 Mar 2000) |
| rosette test | A test for rosette-forming cells (T-lymphocytes) in which these cells and sheep erythrocytes, are incubated and centrifuged lightly, then examined under a microscope for rosette formation or adherence of erythrocytes to T lymphocytes. (05 Mar 2000) |
| Rose-Waaler test | A test of historical interest: when sheep red cells are suspended in a concentration of antiserum to sheep red cells which is too low to cause agglutination, the addition of serum from a patient with rheumatoid arthritis will cause agglutination. (05 Mar 2000) |
| Ross-Jones test | A test for an excess of globulin in the cerebrospinal fluid; 1 ml of cerebrospinal fluid is carefully floated over 2 ml of a concentrated ammonium sulfate solution; if globulin is present in excess, a fine white ring appears at the line of junction in about 3 min. (05 Mar 2000) |
| rotavirus antigen test | <investigation, microbiology> A test which detects the presence of rotavirus in the stool. This virus is a common cause of childhood gastroenteritis. (17 Dec 1997) |
| rotavirus stool test | <investigation> A test which detects the presence of rotavirus in the stool. This virus is a common cause of childhood gastroenteritis. (17 Dec 1997) |
| Rothera's nitroprusside test | A test for ketone bodies; 5 ml of fresh urine are saturated with solid ammonium sulfate and mixed with 10 drops of freshly prepared 2% sodium nitroprusside solution, which is then mixed with 10 drops of concentrated ammonia water and allowed to stand for 15 min; the presence of acetoacetic acid, or of larger concentrations of acetone, is indicated by the development of a blue-purple colour. (05 Mar 2000) |
| phenolsulfonphthalein test | An obsolete test for renal function; after the patient has drunk a glass or two of water, 1 ml of a 0.6% solution of dye is injected hypodermically; the time between this injection and the appearance of a pink tinge in the urine as it falls into an alkaline solution is noted; the amount excreted in each of the next 2 hours is then estimated colourimetrically. Synonym: Geraghty's test, phthalein test, red test, Rowntree and Geraghty test. (05 Mar 2000) |
| phentolamine test | A test for pheochromocytoma; intravenous administration of phentolamine (5 mg) reduces hypertension due to a pheochromocytoma but not that due to other causes, e.g., essential hypertension; the blood pressure is raised by the drug in the latter form of hypertension. (05 Mar 2000) |