ALPHA-1-ANTITRYPSIN PHENOTYPE (INCLUDES ALPHA-1-ANTITRYPSIN)
- ALPHA-1-ANTITRYPSIN PHENOTYPE (INCLUDES ALPHA-1-ANTITRYPSIN)
- Start Date
- Expiration Date
- A1AT Phenotype
- CPT Codes
- 82103, 82104
- Reference Test
- Transport Info
Centrifuge and immediately transfer serum to separate plastic tube
- Fasting Required?
- Patient Instructions
- Reference Range
Alpha-1-Antitrypsin: 100-200 mg/dL
Phenotype: By report
Note: Interpret with caution if the patient has been transfused within the previous 21 days.
Evaluation of hereditary alpha1-antitrypsin deficiency - associated with chronic obstructive pulmonary disease (COPD), hepatic cirrhosis, and hepatoma.
Alpha-1-antitrypsin (A1A; alpha-1-protease inhibitor) is the major protease (trypsin, chymotrypsin, elastase) inhibitor in human serum. It is an acute phase reactant synthesized by the liver, whose inherited deficiency is associated with liver and lung disease. Low levels are also found in neonatal respiratory distress syndrome and severe protein-losing disorders. More than 60 alleles of the A1A locus have been described. The alleles are named according to their electrophoretic mobility. Of all these variants, only S, Z, and the subtypes M(M1, M2, M3) have polymorphic frequencies in most populations. The remainder of the variants are rare. Clinically, the most important phenotypes are MM, MS, SS, MZ, ZZ and rare ("null"), associated with 100%, 80%, 60%, 57.5%, 15%, and 0% A1A activity, respectively. The anti-elastase activity of A1A is physiologically the most important. A1A forms a complex with the protease, inactivating it and allowing for clearance of the complex. Deficiency predisposes to the early onset of panacinar emphysema in young adults and to liver disease in children. Neonatal hepatitis with cholestatic jaundice appears in approximately 10% of all newborns with the deficiency. In some adults, A1A deficiency is complicated by cirrhosis, liver cancer, rheumatoid arthritis, and pancreatitis. As an acute-phase reactant, A1A increases in response to inflammation. In individuals with reduced A1A levels, the action of elastase is unopposed and there is increased connective tissue breakdown.