Used in laboratories to detect and quantify substances such as peptides, proteins, antibodies, and hormones in biological samples. Commonly applied in medical diagnostics to identify infections like HIV, hepatitis, and Lyme disease. Also used in research settings to measure cytokine levels, monitor immune responses, and validate protein expression. Food industry uses it to detect allergens such as peanuts or gluten. Provides a sensitive and high-throughput method for screening large numbers of samples with relatively low cost.