Used in biomedical research to measure levels of BAFF (B cell activation factor) in human serum, plasma, or cell culture samples. Helps in studying autoimmune diseases such as lupus, rheumatoid arthritis, and Sjögren's syndrome, where elevated BAFF levels are linked to abnormal B cell activity. Also used in clinical labs and drug development to monitor disease progression and evaluate the effectiveness of therapies targeting the BAFF pathway. Provides a sensitive and specific method for quantifying soluble BAFF protein, supporting immunological research and diagnostic applications.