What determines the specificity of an immunoassay?

The specificity of an immunoassay is primarily determined by the antibody used in the assay. Antibodies are designed to bind to specific epitopes, which are unique parts of an antigen. The binding between the antibody and its specific epitope is highly selective, allowing for the detection of particular antigens within a sample even when other substances are present. This characteristic is crucial for ensuring that the immunoassay accurately identifies and quantifies the target antigen without interference from similar molecules.

While the type of antigen, incubation time, and pH level can influence the overall performance and sensitivity of the assay, they do not define its specificity. The choice of antibody, which can be tailored through techniques such as hybridoma technology or recombinant DNA technology, directly impacts which antigen is detected and how effectively this detection occurs. Thus, the antibody's affinity for its target and its ability to distinguish between similar structures is what fundamentally provides the specificity required for reliable immunoassay results.