Alpha one antitrypsin phenotype
(α1-AT)

Sample type:

Serum.

Test use:

Detection of hereditary decreases in the production of α1-antitrypsin (α1AT). Decreased or nearly absent levels of α1AT can be a factor in chronic obstructive lung disease and liver disease. An increased prevalence of non-MM phenotypes is found with cryptogenic cirrhosis and with CAH. Cirrhosis in a child should raise consideration of α1AT deficiency or Wilson’s disease. Diagnosis of inflammatory states, if elevated (eg, rheumatoid arthritis, bacterial infection, vasculitis, neoplasia).

Precautions:

Overnight fasting is preferred.

Interfering factors:

α1AT may be elevated into normal range in heterozygous deficient patients during concurrent infection, pregnancy, estrogen therapy, steroid therapy, cancer, and during postoperative periods. Homozygous deficient patients will not show such elevation. Normal α1AT levels may occur in patients with liver disease who are heterozygotes. In normals, pregnancy and contraceptive medication may elevate levels. Levels are normally low at birth but rise soon thereafter.

Pre analytical errors:

1) Improper sample preparation.

2) Inappropriate storage.

Post analytical errors:

1) Delayed report

Corrective actions:

If CRP is positive, retest α1AT in 10 to 14 days.