ELISA kits are widely used in medical and biological research for detecting and quantifying substances such as peptides, proteins, antibodies, and hormones. They are essential in diagnosing infectious diseases like HIV, hepatitis, and Lyme disease by identifying specific antigens or antibodies in blood samples. These kits are also used in food industry testing to detect allergens such as peanuts or gluten. In pharmaceutical development, ELISA kits help monitor drug levels and immune responses during clinical trials. Their high sensitivity and specificity make them valuable in both laboratory and clinical settings for reliable, high-throughput analysis.