Used for detecting and quantifying specific proteins, antibodies, or antigens in biological samples such as serum, plasma, cell lysates, and tissue extracts. 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 discovery. Widely utilized in pharmaceutical development for monitoring immune responses during clinical trials. Offers high sensitivity and specificity, making it a standard tool in both clinical and laboratory environments.