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. In clinical laboratories, ELISA kits provide a reliable method for screening patient samples due to their high sensitivity and specificity. They are also used in food industry testing to detect allergens such as peanuts or gluten. Pharmaceutical companies use ELISA kits during drug development to monitor immune responses and assess biomarker levels. Their ease of use, scalability, and ability to process multiple samples simultaneously make them a standard tool in both research and quality control settings.