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Test Code AAT-PHENO Alpha-1-Antitrypsin Phenotype, Serum

Additional Codes

Mayo Test ID
A1APP

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

See Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm in Special Instructions.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


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 Special Container
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 or not 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.

 

Most normal individuals have the M phenotype (M, M1, or M2). Over 99% of M phenotypes are genetically 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.

 

See Alpha-1-Antitrypsin-A Comprehensive Testing Algorithm in Special Instructions.

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).

 

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

Cautions

This assay identifies the phenotype of the circulating alpha-1-antitrypsin (A1A) protein. If the patient is already on replacement therapy, the phenotype will detect patient and replacement protein.

                         

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

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)