Used in research settings to quantify free Protein S levels in human plasma samples. Helps in studying coagulation disorders, particularly inherited or acquired Protein S deficiencies linked to increased risk of venous thrombosis. Supports investigation into thrombophilia, recurrent miscarriages, and other conditions associated with abnormal blood clotting. Provides a reliable, sensitive method for measuring free Protein S antigen, which is critical for accurate diagnosis and monitoring in clinical research. Not intended for diagnostic use.