Used for detecting and quantifying specific proteins, antibodies, or antigens in biological samples such as serum, plasma, or cell culture supernatants. Commonly applied in medical diagnostics to identify infectious diseases like HIV, hepatitis, and Lyme disease. Also used in research settings to measure cytokine levels, hormone concentrations, and biomarker validation. Widely utilized in pharmaceutical development for monitoring immune responses during clinical trials. Offers high sensitivity and specificity with relatively low sample volume requirements. Suitable for high-throughput screening in laboratories due to compatibility with automated plate readers.