Used in biomedical research to quantify levels of FAS/CD95, a key protein involved in apoptosis, in biological samples such as serum, plasma, and cell lysates. Helps researchers study programmed cell death pathways, particularly in immune regulation and cancer development. Widely applied in studies of autoimmune diseases, neurodegenerative disorders, and drug-induced cytotoxicity. Enables high-throughput screening of compounds that modulate apoptotic signaling. Provides a reliable and sensitive method for detecting soluble FAS antigen, supporting both basic research and preclinical evaluation of therapeutic agents targeting cell death mechanisms.