Alpha1-Antitrypsin Test (AAT)

Alpha1-antitrypsin (AAT) is a protein produced by the liver. It has a protective function, in that it prevents the release of proteolytic enzymes that can damage tissues such as that of the lung. AAT deficiency can be inherited or acquired. When an inherited problem, AAT deficiency is most often noted in individuals of European descent and is first noted relatively early in life. Acquired AAT deficiency is seen in patients who have protein-deficiency syndromes such as liver disease, nephrotic syndrome, and malnutrition. Regardless of the type, the deficiency of AAT allows proteolytic enzymes to damage lung tissue, resulting in severe emphysema in young adulthood.