Alpha-1 Antitrypsin

Diagnostic Use

Diagnosis of alpha-1 antitrypsin deficiency.

Alpha-1 antitrypsin (AAT) 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 AAT is associated with the development of emphysema at an unusually early age and with an increased incidence of neonatal hepatitis, usually progressing to cirrhosis.

Department

Protein Lab

Delphic Registration Code

AAT

Synonyms

Antitrypsin
AAT
A1A

Turnaround Time

4 days

Specimen Type

• Serum
• Plasma

Specimen Requirements

Tube/Container Type:

Preferred

• Serum (Red Cap)

Acceptable

• SST II (Gold Cap)
• Lithium Heparin - Non-gel (Green Cap)
• Lithium Heparin - Gel (Light Green Cap)
• EDTA (Lavender Cap)

Preferred Sample Volume (ml)

0.5

Minimum Sample Volume (ml)

0.25

No of Samples Required

1

Aliquot Instructions

Sample Type

• Serum
• Plasma

Minimum Volume (ml)

0.25

Transport to Lab

Chilled (2 - 8 degrees Celsius)

Interpretation

Patients with serum AAT concentrations less than 0.7 g/L may have a homozygous deficiency and are at increased risk for early lung disease. Alpha-1 antitrypsin phenotyping will be added to confirm the presence of homozygous deficiency alleles.

Patients with serum AAT concentrations ≤ 1.2 g/L will be phenotyped in order to identify heterozygous individuals. Heterozygotes do not appear to be at increased risk for early emphysema.

Low alpha-1 antitrypsin (AAT) concentrations may result from liver disease and AAT phenotyping will be performed to confirm AAT deficiency disease.

AAT is an acute-phase reactant and any inflammatory process will elevate serum AAT concentrations even if the patient is carrying one or more alleles associated with AAT deficiency.

Reference Intervals

1.0 – 2.0 g/L

Test Method

Quantitation by nephelometric immunoassay on Siemens BNII.

Non-Funded Test Cost

$17.05 (Exclusive of GST)

Billing Code

3211

Contact Information

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