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 research settings, ELISA kits help measure cytokine levels, monitor immune responses, and validate protein expression in cell cultures. Their high sensitivity and specificity make them a reliable tool in clinical diagnostics and quality control processes.