assay /as·say/ (as´a) determination of the amount of a particular constituent of a mixture, or of the potency of a drug.
Enzyme-linked immunosorbent assay (ELISA)
enzyme-linked immunosorbent assay (ELISA),
assay [as´a]
biological assay bioassay.
CH50 assay a test of total complement activity as the capacity of serum to lyse a standard preparation of sheep red blood cells coated with antisheep erythrocyte antibody. The reciprocal of the dilution of serum that lyses 50 per cent of the erythrocytes is the whole complement titer in CH50 units per milliliter of serum.
enzyme-linked immunosorbent assay see ELISA.
microbiological assay assay by the use of microorganisms.
microcytotoxicity assay one using the pattern of lysis of peripheral blood lymphocytes in the presence of complement and typing sera to type serologically defined HLA antigens (HLA-A, -B, and -C antigens).
radioimmunoprecipitation assay (RIPA) immunoprecipitation conducted with radiolabeled antibody or antigen.
radioligand assay any assay procedure that uses radioisotopic labeling and biologically specific binding of reagents.
stem cell assay a measurement of the potency of antineoplastic drugs, based on their ability to retard the growth of cultures of human tumor cells.
| enzyme-linked immunosorbent assay n. ELISA. |
Enzyme-linked immunosorbent assay (ELISA)
A diagnostic blood test used to screen patients for AIDS or other viruses. The patient's blood is mixed with antigen attached to a plastic tube or bead surface. A sample of the patient's blood serum is added, and excess proteins are removed. A second antibody coupled to an enzyme is added, followed by a chemical that will cause a color reaction that can be measured by a special instrument.
Mentioned in: AIDS Tests, Giardiasis
enzyme-linked immunosorbent assay (ELISA),
a laboratory technique for detecting specific antigens or antibodies by using enzyme-labeled immunoreactants and a solid-phase binding support, such as a test tube. A number of different enzymes can be used, including carbonic anhydrase, glucose oxidase, and alkaline phosphatase. Labeling is done by covalently binding the enzyme to the test substance through an enzyme-protein coupling agent such as glutaraldehyde. Products of the reaction may be detected by fluorometry or photometry. ELISA is nearly as sensitive as radioimmunoassay and more sensitive than complement fixation, agglutination, and other techniques. It is commonly used in the diagnosis of human immunodeficiency virus infections.
ELISA
Enzyme-Linked Immunosorbent Assay. An immunoenzymatic assay used to measure antigens and antibodies which approaches the sensitivity of RIA
Pros Lower cost, simpler equipment, faster ‘turn-around time’, and none of the problems inherent in handling radioactive substances
Pros Lower cost, simpler equipment, faster ‘turn-around time’, and none of the problems inherent in handling radioactive substances
assay [as´a]
determination of the purity of a substance or the amount of any particular constituent of a mixture.
biological assay bioassay; determination of the potency of a drug or other substance by comparing the effects it has on animals with those of a reference standard.
CH50 assay a test of total complement activity as the capacity of serum to lyse a standard preparation of sheep red blood cells coated with antisheep erythrocyte antibody. The reciprocal of the dilution of serum that lyses 50 per cent of the erythrocytes is the whole complement titer in CH50 units per milliliter of serum.
enzyme-linked immunosorbent assay (ELISA) any enzyme immunoassay using an enzyme-labeled immunoreactant (antigen or antibody) and an immunoadsorbent (antigen or antibody bound to a solid support). A variety of methods are used for measuring the unknown concentration, such as either competitive binding between the labeled reactant and unlabeled unknown or a sandwich technique in which the unknown antigen binds both the immunoadsorbent and labeled antibody. One of the uses of ELISA is to screen blood for antibody to the human immunodeficiency virus; a positive result indicates probable exposure to the virus and possibly that the virus is in the blood. Since false-positives can occur, a back-up test is used to confirm positive findings.
ELISA: With antigen capture ELISA, the wells are coated with antibody to the virus. The sample containing virus (1) is added and, after washing several times, enzyme conjugated to an antibody to the virus is added (2). Finally, after a further cycle of washing, the enzyme's substrate (3) is added. A colored product is formed if the viral antigen is present in the sample (4). From Hart and Shears, 1997.
microhemagglutination assay–Treponema pallidum (MHA-TP) a Treponema pallidum hemagglutination assay using microtechniques; used in the detection of syphilis.
radioreceptor assay a radioligand assay in which a radiolabeled hormone is used to measure the concentration of specific cellular receptors for the hormone in tissue specimens, an example being radioassay of estrogen receptors in breast tissue.
thyroid-stimulating hormone assay thyroid-stimulating hormone test.
Treponema pallidum hemagglutination assay (TPHA) a treponemal antigen serologic test for syphilis using tanned sheep red blood cells coated with antigen from the Nichol's strain of Treponema pallidum and treated patient serum; it is similar in sensitivity and specificity to the FTA-ABS test. This test is not useful for individuals who have had syphilis in the past.
TSH assay thyroid-stimulating hormone test.
enzyme-linked immunosorbent assay (enˑ·zīm-linkd′ imˈ·myun·ō·sorˑ·b
nt aˑ·say),n technique used to identify particular antibodies or antigens using enzyme-labeled immunoreactants. Reaction products are recorded by photometry or fluorometry. Commonly used to diagnose HIV infections.
)
Enzyme-linked immunosorbent assay.
enzyme (en´zīm),
n a protein substance that acts as a catalyst to speed up metabolic and other processes involving organic materials. Some enzymes function within cells; others function in the extracellular fluids and tissue spaces and organs. They are active in all major tissue functions, such as cellular respiration, muscle contraction, digestive processes, and energy consumption, and are produced intracellularly.
enzyme-linked immunosorbent assay (ELISA),
n a species-specific serologic laboratory procedure used to identify microorganisms infecting or inhabiting a tissue or organ system. Its dental use is in the identification of pathogens involved in periodontal disease.
Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|