ELISA kit is widely used in medical and biological research for detecting and quantifying substances such as peptides, proteins, antibodies, and hormones. It is commonly applied in diagnosing infectious diseases like HIV, hepatitis, and Lyme disease by identifying specific antigens or antibodies in blood samples. In clinical laboratories, ELISA kits support autoimmune disease testing, including rheumatoid arthritis and lupus, by measuring autoantibodies. 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 protein expression and assess immune responses. Due to their high sensitivity and ease of use, these kits are essential in both research and quality control settings.