The Serum Alpha-1 Antitrypsin test measures the levels of a protease inhibitor, Alpha-1 antitrypsin. This inhibitor actively impedes the activity of a series of proteases, exhibiting anti-inflammatory, anti-apoptotic, anti-oxidative stress, and anti-bacterial properties. This test is used to diagnose conditions including alpha-antitrypsin deficiency, rheumatoid arthritis, gouty arthritis, systemic lupus erythematosus, multiple sclerosis, systemic vasculitis and acute graft versus host disease.