Labled Immunoassays

patient antigen competes with labeled antigen for limited antibody-binding sites

inverse ratio: the more patient antigen is present, the less the label detected.

Excess solid-phase antigen binds patient antibody and a second lableled antibody is added.

All patient antibody is allowed to bind. Amount of label is directly proportional to the amount of patient antibody present.

excess solid-phase antibody binds patient antigen and a second labeled antibody is added.

All patient antibody is allowed to bind. Amount of label is directly proportional to the amount of patient antibody present.

patient antigen and enzyme - labeled antigen react with reagent antibody in solution. Enzyme label is inactivated when reagent antigen binds to antibody.

no separation step.
Antibody in solution.
Inverse ratio between patient antigen and amount of label detected.

Patient antigen is attached to a slide. Specific fluorescent - labeled antibody is added.

if fluorescence is detected, patient antigen is present and the test is positive.

reagent antigen is attached to a slide. Patient antibdoy is allowed to react. A second fluorescent-labeled antibody is added.

If fluorescence is detected, patient antibody is present and the test is positive.

Fluorescent-labled antigen competes with patient antigen for a limited number of soluble antibody-binding sites.

when patient antigen binds, less reagent antigen binds and less polarization will be detected. Inverse ratio between patient antigen and amount of polarization.

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.

If test is positive, a line or plus sign will form on the test strip where patient antigen or antibody is captured.