assay (as´sa, a-sa´)
1. Test of purity; trial. 2. To examine; to subject to analysis. 3. The quantitative or qualitative evaluation of a substance for impurities, toxicity, etc; the results of such an evaluation. [M.E>, fr. O>Fr. essaier, fr. L>L> exagium, a weighing]
Ames a. Ames test
biological a. biotest
clonogenic a. in vitro culturing of neoplastic cells to test their radiosensitivity or chemosensitivity, and probable clinical efficacy of a therapeutic agent.
competitive binding a. general term for an a. in which a binder competes for labeled versus unlabeled ligand; following separation of free and bound ligand, the ligand (the analyte assayed) is quantitated by relating bound and unbound ratios to known standards. See also enzyme-linked immunosorbent a., radioreceptor a., immunoassay, enzyme-multiplied immunoassay technique, radioimmunoassay.displacement analysis, saturation analysis;
complement binding a. a test for the detection of immune complexes.
double antibody sandwich a. 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 unlabeled known antibody, the attachment of which to the antigen can be demonstrated by addition of immunoglobulin-specific antibody linked to the enzyme.
EAC rosette a. (ro-zet´ as´sa) See EAC rosette.
enzyme-linked immunosorbent a. (ELISA) a sensitive method for serodiagnosis of specific infectious diseases; an in vitro competitive binding a. in which an enzyme and its substrate serve as the indicator system rather than a radioactive substance; in positive tests, the two yield a colored or other easily recognizable substance; tests are made in wells in polystyrene or other material to which immunoglobulins or antigenic (viral or other) preparations readily adsorb; the enzyme is linked to known immunoglobulin (or antigen) and in positive tests remains in the well as part of the antigen-antibody complex available to react with its substrate when added.
Grunstein-Hogness a. a procedure for identifying plasmid clones by colony hybridization.
hemizona a. (hem´e-zo-na) diagnostic test evaluating the binding capacity of sperm to the zona pellucida.
immunochemical a. immunoassay
immunoradiometric a. an a. that differs from conventional radioimmunoassay in that the compound to be measured combines directly with radioactively labeled antibodies.
indirect a. 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.
Lowry-Folin a. Lowry protein a
Lowry protein a. a method for determining protein concentrations using the Folin-Ciocalteu reagent.Lowry-Folin a;
radioreceptor a. a competitive binding a. in which the binder is a membrane or tissue receptor rather than an antibody.
Raji cell radioimmune a. for immune complexes; a procedure by which immune complexes adsorbed from a test serum by a standard preparation of lymphoblastoid (Raji) cells are assayed by the capacity to bind 125I-labeled antibody to immunoglobulin.
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