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Test Code AAT Alpha-1-Antitrypsin, Serum

Additional Codes

Mayo Test ID
AAT

Reporting Name

Alpha-1-Antitrypsin, S

Useful For

Workup of individuals with suspected disorders such as familial chronic obstructive lung disease

 

Diagnosing alpha-1-antitrypsin deficiency

Testing Algorithm

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

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 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

100-190 mg/dL

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

LOINC Code Information

Test ID Test Order Name Order LOINC Value
AAT Alpha-1-Antitrypsin, S 6771-0

 

Result ID Test Result Name Result LOINC Value
AAT Alpha-1-Antitrypsin, S 6771-0

Clinical Information

Alpha-1-antitrypsin (A1A) is the most abundant serum protease inhibitor, and it 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.

 

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

Interpretation

Patients with serum levels less than 70 mg/dL may have a homozygous deficiency and are at risk for early lung disease. Alpha-1-antitrypsin proteotype testing should be done to confirm the presence of homozygous deficiency alleles.

 

If clinically indicated, patients with serum levels less than 125 mg/dL should have proteotype testing in order to identify heterozygous individuals. Heterozygotes do not appear to be at increased risk for early emphysema.

Cautions

Low alpha-1-antitrypsin (A1A) levels may result from liver disease, and A1A proteotype testing should be done to confirm A1A deficiency disease.

 

A1A is an acute-phase reactant, and any inflammatory process will elevate serum A1A levels.

 

Quantitation of specific proteins by nephelometric means may not be possible in lipemic sera due to the extreme light scattering properties of the specimen. Turbidity and particles in the specimen may result in extraneous light scattering signals, resulting in variable specimen analysis.

Report Available

1 to 3 days

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK

Method Name

Nephelometry