Used in biomedical research to quantify soluble Fas ligand (sFasL) levels in biological samples such as serum, plasma, and cell culture supernatants. Helps investigate immune regulation, apoptosis, and inflammatory processes. Commonly applied in studies of autoimmune diseases, cancer progression, and transplant rejection where dysregulation of cell death pathways plays a critical role. Provides a reliable, sensitive, and specific method for monitoring sFasL as a potential biomarker in clinical and experimental settings.