Test Details
Methodology
Immunologic
Result Turnaround Time
1 - 2 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
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).
Limitations
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.
Contraindications
If CRP is positive, retest α1AT in 10 to 14 days.
Custom Additional Information
Should be run when α1-globulin in serum protein electrophoresis is low or when two bands are seen in the α1-region. Heterozygous patients exhibit AAT levels which are commonly about 60% of normal. Homozygous recessive α1AT patients exhibit levels at about 10% of normal. Phenotyping is desirable on patients with low values and on all patients being worked up for AAT-deficient liver disease. Most pathologic is homozygous state ZZ. An M null genotype will have phenotype as MM but low serum level. AAT is one of the alpha-globulins, which together are called “acute phase reactants.” These rise rapidly, but nonspecifically, in response to inflammatory insults.
Specimen Requirements
Specimen
Serum (preferred) or plasma
Volume
1 mL
Minimum Volume
0.3 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (heparin) tube
Collection Instructions
Separate serum or plasma from cells.
Stability Requirements
| Temperature | Period |
|---|---|
| Room temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
| Freeze/thaw cycles | Stable x3 |
Reference Range
See table.
| Age | Male mg/dL | Female mg/dL |
|---|---|---|
| 0 to 7 d | 102–186 | 102–186 |
| 8 to 30 d | 73–187 | 73–187 |
| 31 d to 5 y | 86–173 | 86–173 |
| 6 to 12 y | 99–156 | 99–156 |
| 13 to 40 y | 95–164 | 100–188 |
| >40 y | 101–187 | 101–187 |
Storage Instructions
Maintain specimen at room temperature.
Patient Preparation
Overnight fasting is preferred.
Causes for Rejection
Chylous serum
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 001982 | Alpha-1-Antitrypsin, Serum | 1825-9 | 001982 | Alpha-1-Antitrypsin, Serum | mg/dL | 1825-9 |
| Order Code | 001982 | |||||
| Order Code Name | Alpha-1-Antitrypsin, Serum | |||||
| Order Loinc | 1825-9 | |||||
| Result Code | 001982 | |||||
| Result Code Name | Alpha-1-Antitrypsin, Serum | |||||
| UofM | mg/dL | |||||
| Result LOINC | 1825-9 |