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| 80425:ALPHA-1-ANTITRYPSIN PHENOTYPE (INCLUDES ALPHA-1-ANTITRYPSIN) | |||||||||
| Methodology: | Isoelectric Focusing/Immunoturbidimetric | ||||||||
| Edit Date: | 11/24/2008 | ||||||||
| Performed: | Monday, Wednesday, Friday | ||||||||
| Released: | 2-4 days after setup at PeaceHealth Laboratories’ reference lab. | ||||||||
| CPT Code: | 82103-90 / 82104-90 | ||||||||
| Specimen Collection Details | |||||||||
| Collection: | One 7.5 mL serum separator tube (SST). | ||||||||
| Handling: | Allow to clot, centrifuge and separate serum from cells and pour into a plastic vial. Freeze. Avoid repeated freeze/thaw cycle. | ||||||||
| Stability: | 8 hours ambient, 5 days refrigerated, or 14 days frozen. | ||||||||
| Standard Volume: | 1 mL serum. | ||||||||
| Minimum Volume: | 300 µL serum. | ||||||||
| Transport: | Frozen on dry ice. | ||||||||
| Comments: | Interpret with caution if patient has been transfused within the previous 21 days. | ||||||||
| Phenotype | Alpha-1-Antitrypsin | ||||||||||||||||||
| By report | 100-200 mg/dL | ||||||||||||||||||
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Interpretative Data: 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.
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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.
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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.
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