1What is the principle of competitive assay?
patient antigen competes with labeled antigen for limited antibody-binding sites
2What is the results of competitive assay?
inverse ratio: the more patient antigen is present, the less the label detected.
3What is the principle of noncompetitive assay or indirect ELISA?
Excess solid-phase antigen binds patient antibody and a second lableled antibody is added.
4What is the results of noncompetitive assay or indirect ELISA?
All patient antibody is allowed to bind. Amount of label is directly proportional to the amount of patient antibody present.
5What is the principle of capture or sandwich assay??
excess solid-phase antibody binds patient antigen and a second labeled antibody is added.
6What is the results of capture or sandwich assay?
All patient antibody is allowed to bind. Amount of label is directly proportional to the amount of patient antibody present.
7What is the principle of homogenous assay?
patient antigen and enzyme - labeled antigen react with reagent antibody in solution. Enzyme label is inactivated when reagent antigen binds to antibody.
8What is the results of homogenous assay?
no separation step.
Antibody in solution.
Inverse ratio between patient antigen and amount of label detected.
9What is the principle of direct fluorescent assay?
Patient antigen is attached to a slide. Specific fluorescent - labeled antibody is added.
10What is the result of direct fluorescent assay?
if fluorescence is detected, patient antigen is present and the test is positive.
11What is the principle of indirect fluorescent assay?
reagent antigen is attached to a slide. Patient antibdoy is allowed to react. A second fluorescent-labeled antibody is added.
12What is the result of indirect fluorescent assay?
If fluorescence is detected, patient antibody is present and the test is positive.
13What is the principle of fluorescent polarization assay?
Fluorescent-labled antigen competes with patient antigen for a limited number of soluble antibody-binding sites.
14What is the results of fluorescent polarization assay?
when patient antigen binds, less reagent antigen binds and less polarization will be detected. Inverse ratio between patient antigen and amount of polarization.
15What is the principle of immunochromatographic assay?
Patient sample is added to a test strip and migrates through the strip. Labeled antigen or antibody binds and is captured by a second reagent in the detection zone.
16What is the results of immunochromatographic assay?
If test is positive, a line or plus sign will form on the test strip where patient antigen or antibody is captured.