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Test Code 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.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

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.

Cautions

This assay identifies the phenotype of the circulating alpha-1-antitrypsin (A1A) protein. If the patient is already on replacement therapy or has recently been transfused, the phenotype will detect patient and replacement or transfused plasma A1A protein. This test also cannot detect a null allele which could be responsible for an A1A deficiency.

 

If 2 bands are seen, such as an M band and a Z bands, it is reported as MZ (eg, heterozygous)

 

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.

Report Available

2 to 6 days

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK

Method Name

A1AP2: Isoelectric Focusing

AATP: Nephelometry

Secondary ID

26953

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)