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Test ID: A1APP Alpha-1-Antitrypsin Phenotype, Serum

Reporting Name

Alpha-1-Antitrypsin Phenotype

Useful For

Identification of homozygous and heterozygous phenotypes of the alpha-1-antitrypsin deficiency

Profile Information

Test ID Reporting Name Available Separately Always Performed
A1AP2 Alpha-1-Antitrypsin Phenotype No Yes
AATP Alpha-1-Antitrypsin, S Yes, (Order AAT) Yes

Testing Algorithm

For information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.25 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reference Values

ALPHA-1-ANTITRYPSIN

100-190 mg/dL

 

ALPHA-1-ANTITRYPSIN PHENOTYPE

The interpretive report will identify the alleles present. For rare alleles, the report will indicate whether they have been associated with reduced quantitative levels of alpha-1-antitrypsin.

Day(s) Performed

Monday through Friday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

82103

82104

LOINC Code Information

Test ID Test Order Name Order LOINC Value
A1APP Alpha-1-Antitrypsin Phenotype 32769-2

 

Result ID Test Result Name Result LOINC Value
AATP Alpha-1-Antitrypsin, S 6771-0
8166 Alpha-1-Antitrypsin Phenotype 32769-2

Clinical Information

Alpha-1-antitrypsin (A1A) is the most abundant serum protease inhibitor and inhibits trypsin and elastin, as well as several other proteases. The release of proteolytic enzymes from plasma onto organ surfaces and into tissue spaces results in tissue damage unless inhibitors are present. Congenital deficiency of A1A is associated with the development of emphysema at an unusually early age and with an increased incidence of neonatal hepatitis, usually progressing to cirrhosis.

 

The gene for A1A appears to be coded at a single locus whose alleles are inherited in a co-dominant manner. Most normal individuals have the M phenotype (M, M1, or M2). Over 99% of M phenotypes are genetically homozygous M (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.

 

For more information see Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm.

Interpretation

There are greater than 40 alpha-1-antitrypsin (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 greater than 90% of individuals of European descent are genetically homozygous M (MM).

 

Alpha-1-antitrypsin deficiency is usually associated with the Z phenotype (homozygous ZZ), but SS and SZ are also associated with decreased A1A levels.

Clinical Reference

1. Morse JO. Alpha-1-antitrypsin deficiency. N Engl J Med. 1978;299:1045-1048;1099(20) 1099-1105

2. Donato LJ, Jenkins SM, Smith C, et al. Reference and interpretive ranges for alpha(1)-antitrypsin quantitation by phenotype in adult and pediatric populations. Am J Clin Pathol.2012;138(3):398-405

3. Stoller JK, Lacbawan FL, Aboussouan SF: Alpha-1 antitrypsin deficiency. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews.[Internet]. University of Washington, Seattle; 2006. Updated June 1, 2023. Accessed May 21, 2025. Available at www.ncbi.nlm.nih.gov/books/NBK1519/

4. Rosenberg W, Badrick T, Tanwar S: Liver disease. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1348-1397

Report Available

2 to 6 days

Method Name

A1AP2: Isoelectric Focusing

AATP: Nephelometry

Forms

If not ordering electronically, complete, print, and send 1 of the following with the specimen:

-Gastroenterology and Hepatology Test Request (T728)

-General Request (T239)

Mayo Clinic Laboratories | Gastroenterology Catalog Additional Information:

mml-gi-liver-genetic