Laboratory Test Information Guide

Details for Alpha 1-Antitrypsin Phenotype, Serum

Test Name: Alpha 1-Antitrypsin Phenotype, Serum
Alternate Name(s): Alpha-1 Antitrypsin Phenotype
Alpha-1-Antitrypsin Phenotype
Alpha1 Antitrypsin Phenotype
Alpha 1 Antitrypsin Phenotype
A1AT Phenotyping
Alpha 1-Antitrypsin Proteotype
Laboratory: Core
Specimen Type: Adult:
5 mL Gold top Vacutainer tube

0-2 years: 2 x 0.5 mL Red or Gold top Microtainer
2-10 years: 3 mL Red Vacutainer top
Collection Information: Serum drawn from a fasting individual is preferred.

Minimum volume of serum required is 1.5 mL for an adult sample and 0.5 mL for a pediatric sample.
Test Schedule: Referred out Monday-Thursday
Turnaround time from when specimen
is received in testing laboratory:
2 weeks
Reference Range: Alpha-1-Antitrypsin: 100 - 190 mg/dL (reference interval from Mayo Medical Laboratories)
Proteotype: Negative for S and Z phenotypes (Non S Non Z)
Effective Date: 2010-01-21
Revised Date: 2019-11-07
Critical Value:  
Interpretive Comments: This assay will not detect 5% of the known mutations that cause alpha 1-antitrypsin (A1AT) deficiency. Therefore, the absence of a detectable mutation does not rule out the possibility that an individual is a carrier of, or affected with, this disease.

Errors in interpretation may occur if patients have had a recent blood transfusion or are on alpha 1-antitrypsin replacement therapy.
Special Processing:  
Comments: This test is available exclusively to LHSC/SJHC physicians.

All specimens submitted for A1AT phenotyping/proteotyping will have a serum A1AT level measured at LHSC as a screening test. Those specimens with an A1AT result of ≤1.50 g/L will be referred out for proteotyping automatically as long as phenotyping/proteotyping has been ordered and phenotyping/proteotyping has not been done on the patient in the past. If the A1AT level is >1.50 g/L, the sample will not be referred out for phenotyping/proteotyping without biochemist approval.

If Mayo Medical Laboratories finds the mass spectrometry proteotype and quantitative serum level to be discordant, phenotyping (by isoelectric focusing) will be performed.
Method of Analysis: Nephelometry for quantification;
LC-MS/MS for proteotyping (detection of mutated peptides of the S and Z alleles);
Isoelectric focusing for phenotyping (if indicated)
Critical Information Required:  
Storage & Shipment: Store and ship serum frozen.
System Codes: 
Referred To: In-Common Laboratories

Questions? Comments? Contact Laura Gopaul