immünoassay

Immunoassay is a biochemical test that detects or quantifies an analyte in a sample by using the specific binding between an antigen and an antibody. The test translates this binding into a measurable signal, such as color, fluorescence, or radioactivity.

Common formats include enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), fluoroimmunoassay, and chemiluminescent immunoassay, as well as lateral flow immunoassays used in rapid tests. Assays can be designed as sandwich or competitive formats depending on the analyte's properties and the required sensitivity.

Immunoassays are widely used in clinical diagnostics to measure hormones, drugs, infectious agents, and biomarkers; in pregnancy testing via hCG; in veterinary, environmental, and food safety testing; and in research settings to study protein interactions.

Advantages and limitations: They provide high sensitivity and specificity, are scalable for automation, and can be high-throughput. Limitations include potential cross-reactivity, interference from sample components, dependence on antibody quality, and the need for careful calibration and standardization.

History: Immunoassay concepts emerged in the mid-20th century, with the first radioimmunoassay developed by Rosalyn Yalow and Solomon Berson in the 1950s. The approach was later extended to other detection methods, most notably ELISA in the 1970s, expanding its use in medicine and research.

Terminology: In English texts the term immunoassay is standard; immünoassay appears in some languages and transliterations, reflecting language-specific spelling.