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, as well as in research settings for measuring cytokine levels, hormone concentrations, and immune responses. Also utilized in food safety testing to detect allergens or pathogens such as Salmonella and E. coli. Provides a sensitive, high-throughput method suitable for clinical labs and large-scale screening.