| haemolytic plaque assay | <investigation> A haemolytic plaque assay is a lab technique used to show that certain antibodies are secreted by antibody-making cells when these cells are mixed with red blood cells. The mixture is spread onto a plate of agar, if a plaque appears, it means that the red blood cells have been destroyed (by haemolysis) by the antibodies. (09 Oct 1997) |
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| Hageman factor assay | A test used to measure the activity of a blood clotting factor XII. This test may be used to evaluate excessive bleeding. Low factor XII may be seen in cases of congenital deficiency of factor XII, heparin administration and liver disease. (27 Sep 1997) |
| progesterone receptor assay | The progesterone receptor test (PgR assay) checks the tumour for its hormone status. (16 Dec 1997) |
| hemizona assay | <investigation> The hemizona assay is a laboratory test of the ability of sperm to penetrate into a human egg, first the egg is split in half, then one half is tested against the husband's sperm and the other half against sperm from a fertile man. (09 Oct 1997) |
| scintillation proximity assay | Assay system in which antibody or receptor molecule is bound to a bead that will emit light when _ emission from an isotope occurs in close proximity, i.e. From a radioactively labelled ligand. Avoids the need for scintillant in order to measure the amount of bound isotope and thus the amount of antigen or ligand present. (18 Nov 1997) |
| hormone receptor assay | A diagnostic test to determine whether a breast cancer's growth is influenced by hormones or if it can be treated with hormones. (09 Oct 1997) |
| subrenal capsule assay | In vivo method of screening investigative anticancer drugs and biologic response modifiers for individual cancer patients. Fresh tumour tissue is implanted under the kidney capsule of immunocompetent mice or rats; gross and histological assessments follow several days after tumour treatment in situ. (12 Dec 1998) |
| nuclear run off assay | <investigation, procedure> Technique for determining which genes are being actively transcribed at a given moment in an experiment by extracting nuclear material and allowing transcription to continue, then analysing the resulting RNAs. (18 Nov 1997) |
| DNA filter assay | <molecular biology> A lab technique used to identify the complementary base sequences of DNA. It involves immobilising the DNA on a filter and putting it in a solution that contains radioactively-labelled probe DNA or RNA molecules. (09 Oct 1997) |
| double antibody sandwich assay | For antigen; an application of the ELISA method in which material being tested for antigen is added to wells coated with known antibody; the presence of antigen fixed to the antibody coat can be determined either directly, by adding human antibody linked to the enzyme of the indicator system, or indirectly, by first adding unlabelled known antibody, the attachment of which to the antigen can be demonstrated by addition of immunoglobulin-specific antibody linked to the enzyme. (05 Mar 2000) |
| immunochemical assay | <investigation> A process that measures and identifies a specific biological substance such as an antigen. (09 Oct 1997) |
| immunocytochemical assay | Involves the computerised assessment of microscopic fields following direct fluorescent antibody, indirect fluorescent antibody or indirect or direct immunoperoxidase analysis of biopsy tissue from the patient. In addition to improved specificity with the removal of operator subjectivity, the quantifiability of results through computer data analysis of colour, intensity and concentration has only begun to be realised. (05 Mar 2000) |
| immunoradiometric assay | <immunology> A test that measures the concentration of antigens in a specimen throughserological analysis that involves mixing radioactive antibodies with the antigen in question. (09 Oct 1997) |
| indirect assay | For antibody; an application of the ELISA method in which serum being tested for antibody is added to wells coated with known antigen; presence of antibody bound to the antigen coat can be determined by addition of immunoglobulin-specific antibody to which is linked the enzyme of the indicator system, followed by addition of substrate to the washed aggregate. (05 Mar 2000) |
| Ouchterlony assay | <investigation> Immunological test for antigen antibody reactions in which diffusion of soluble antigen and antibody in a gel leads to precipitation of an antigen-antibody complex, visible usually as a whitish band. The system has the advantage that, because of radial diffusion of the reagents, a very wide range of ratios of antigen to antibody concentration develop, thus it is likely that precipitation will occur somewhere in the gel even when no care is taken with quantitation of the system. (18 Nov 1997) |