Immunoassay Classifications

A type of immunoassay that uses two antibodies (capture and detection) to sandwich the target analyte between them. The capture antibody is immobilized on a solid phase, such as a microtiter plate, and the detection antibody is labeled with a signal detectable by instruments like a luminometer or a spectrophotometer.

A technique that relies on the competition between labeled and unlabeled analytes for a limited number of binding sites on an antibody. The amount of labeled analyte bound to the antibody is inversely proportional to the concentration of unlabeled analyte in the sample.

A type of sandwich assay where the capture antibody is immobilized on a solid phase, such as a microtiter plate, while the detection antibody is free in solution and labeled with a detectable signal.

A type of sandwich assay where both the capture and detection antibodies are free in solution, and the signal generation is not reliant on a solid phase.

An antibody conjugated to a molecule that can be readily detected, such as an enzyme or a fluorescent tag, allowing for the quantification of the target analyte.

An antibody immobilized on a solid phase, such as a microtiter plate, that captures the target analyte from the sample.

In a sandwich assay, a high signal indicates a high concentration of the target analyte, demonstrating a direct relationship between the signal intensity and the analyte's concentration.

The ability of an assay to differentiate between the target analyte and other components in the sample, preventing false-positive results.

A category of immunoassays that don't need a label to detect the antibody-antigen complex. They rely on the physical properties of the complex, like size or light scattering.

A process where antibodies and antigens bind, forming a visible clump. It's used in label-free assays to detect the presence of antibodies or antigens.

A type of label-free immunoassay that uses latex beads coated with antigens. When antibodies in the sample bind to the antigens on the beads, they clump together, causing visible agglutination.

A non-competitive immunoassay where an excess of reagents is used, usually antibodies, to capture and detect the target analyte in a sample. It allows for a wider range of analyte concentrations to be measured.

The phenomenon where high concentrations of an analyte can interfere with antibody-antigen complex formation, leading to inaccurate results in label-free immunoassays. It can be overcome by diluting the sample.

A curve that represents the relationship between the concentration of an antigen and the degree of agglutination observed in a latex agglutination assay.

A traditional immunoassay technique that measures the concentration of an analyte by observing the size of the precipitate formed when antibodies and antigens bind. It's generally slower than LAA.

A method used to determine the appropriate dilutions for a sample to ensure it falls within the detectable range of an assay.