Lab Test

Alpha 1 Antitrypsin Phenotyping, Serum

A1A P, Alpha-1 Antitrypsin Phenotyping, Alpha-1-Antitrypsin

Test Codes

EPIC: LAB5931, Beaker: XA1AP, WARDE: A1AP

Department

Send Outs

Specimen Collection Criteria

Collect (preferred specimen): One Gold-top SST tube.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Rejection Criteria

  • Hemolyzed specimens.
  • Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 1.0 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.5 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 14 days

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Warde Medical Laboratory, Ann Arbor, MI.

Performed

Tuesday, Friday.
Results available in 1-4 days.

Reference Range

Alpha-1-Antitrypsin: 90-200 mg/dL.

Alpha-1-Antitrypsin Phenotyping: Most normal individuals have the M phenotype (M, M1, or M2). Over 99% of M phenotypes are genotypically MM. In the absence of family studies, the phenotype (M) and quantitative level can be used to infer the genotype (MM). The most common alleles associated with a quantitative deficiency are Z and S. The reports for the rare alleles will indicate whether or not they have been associated with reduced quantitative levels.

Test Methodology

Isoelectric Focusing/Nephelometric.

Interpretation

There are greater than 40 A1A phenotypes (most of these are associated with normal quantitative levels of protein). The most common normal phenotype is M (M, M1, or M2), and more than 90% of Caucasians are homozygous M (MM) genotype.

A1A deficiency is usually associated with the Z phenotype (ZZ genotype), but genotypes such as SS and SZ are also associated with decreased A1A levels.

Cautions: This assay identifies A1A phenotype as opposed to genotype.

If 2 bands are seen, such as an M band and a Z band, it is reported as MZ (the equivalent of the genotype). If 1 band is seen, such as the Z band and the quantitative level is consistent with a homozygote, the phenotype is assumed to be homozygous and is reported as ZZ.

Clinical Utility

This assay is used to aid in the diagnosis of hereditary alpha-1-antitrypsin deficiency, which is associated with chronic obstructive pulmonary disease (COPD), hepatic cirrhosis, and hepatoma.

CPT Codes

82103 (Alpha-1-Antitrypsin), 82104 (Alpha-1-Antitrypsin Phenotype).
LOINC:  6771-0, 6770-2, 2865-4

Contacts

Last Updated

12/6/2022

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