Used in immunological research to detect and quantify the presence of the human immunoglobulin J-chain in biological samples. The ELISA research kit enables precise measurement of J-chain levels in serum, plasma, or cell culture supernatants, supporting studies on B cell differentiation, antibody production, and mucosal immunity. It is widely applied in clinical research to investigate immune system disorders, autoimmune diseases, and immunodeficiency conditions. The assay provides high sensitivity and specificity, making it suitable for monitoring J-chain expression in response to infections, vaccines, or therapeutic interventions.