| platelet membrane glycoproteins | Surface glycoproteins on platelets which have a key role in haemostasis and thrombosis such as platelet adhesion and aggregation. Many of these are receptors. (12 Dec 1998) |
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| platelet storage pool deficiency | A group of disorders characterised by a decrease or lack of platelet dense bodies in which the releasable pool of adenine nucleotides and 5ht are normally stored. (12 Dec 1998) |
| platelet thrombosis | Thrombosis due to an abnormal accumulation of platelets. (05 Mar 2000) |
| platelet tissue factor | <haematology> Traditional name for substance in plasma that converts prothrombin to thrombin. Now known not to be a single substance. (See thrombin). (18 Nov 1997) |
| platelet transfusion | The transfer of blood platelets from a donor to a recipient or reinfusion to the donor. (12 Dec 1998) |
| low affinity platelet factor IV | Cytokine, produced from platelet basic protein, that acts as a growth factor. (18 Nov 1997) |
| low platelet count | <haematology> An abnormally low platelet count. Normal platelet counts are 150,000-400,000 per cubic millimetre. Those with low platelet counts may exhibit haematuria, haematemesis, easy bruising, bleeding gums, melena (blood in stools), prolonged menses or nosebleeds. Spontaneous intracranial haemorrhage can occur with platelet counts of 10-15,000 (or less). (27 Sep 1997) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |
| achievement test | A standardised test used to measure acquired learning, e.g., competence in a specific subject area such as reading or arithmetic, in contrast to an intelligence test which is a useful index of potential ability or learning. (05 Mar 2000) |
| acidified serum test | Lysis of the patient's red cells in acidified fresh serum, specific for paroxysmal nocturnal haemoglobinuria. Synonym: Ham's test. (05 Mar 2000) |
| acid loading test | <nephrology> This is a test used in the diagnosis of renal tubular acidosis. The patient takes ammonium chloride capsules for 3 days to acidify the blood (lower blood pH). A sample of the urine and the blood is then collected and the results are interpreted. (27 Sep 1997) |
| acid perfusion test | <gastroenterology, investigation> A test used to diagnosis gastrooesophageal reflux disease. This investigation requires that the patient swallow 3 tiny tubes into the stomach. A mixture of hydrochloric acid (like stomach acid) and saline are alternatively injected into the tubes. The patient then reports any symptoms they may have. Some patients may vomit. (13 Nov 1997) |
| acid phosphatase test for semen | A screening test for semen by determining acid phosphatase content; because seminal fluid contains high concentrations of acid phosphatase, while other body fluids and extraneous foreign materials have very low concentrations, high values of acid phosphatase on vaginal aspirate or lavage, or on wash fluid from stains, render positive identification of semen, even if the male is aspermic. (05 Mar 2000) |
| acid reflux test | A test to detect gastroesophageal reflux by monitoring oesophageal pH by an electrode in the distal oesophagus either basally or after acid is instilled into the stomach. (05 Mar 2000) |