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Laboratory Test Reference Guide

Laboratory Information

Test Name

Alpha 1 Antitrypsin

Synonyms

A1AT

External Price (excl. GST)

Price

$14.48

Specimen Collection

Adult Specimen

Gold or Red tube

Paediatric Specimen

Paediatric Gold or Red tube

Instructions for Referral to Waikato Lab

Aliquot Instructions

300uL Serum

Aliquot Transport

Chilled

Test Information

Department

Immunology

Test Availability

Mon - Fri, 0800 - 1630 excl. Public Holidays

Laboratory Turnaround Time

48 hours

Method

Nephelometry

Unit Of Measurement

g/L

Reference Interval

0.8 - 2 g/L

Uncertainty Of Measurement

<10%

Additional Information

A1AT is a protease inhibitor. Deficiency causes unopposed action of leukocyte elastase, causing lung disease. The threshold for lung disease seems to be 0.8 g/L

Testing is done to check for A1AT deficiency. Hereditary deficiency can cause early onset emphysema, neonatal hepatitis or juvenile cirrhosis. A1AT is an acute phase protein; deficiency may be masked if an acute inflammatory process is present. A1At may be decreased due to increased consumption: neonatal respiratory distress syndrome, severe neonatal hepatitis, pre-terminal pancreatic disease or increased loss: nephrotic syndrome or protein losing enteropathy.

Samples are referred for phenotyping (performed at LabPlus) if A1AT is < 0.8 g/L but can also be requested if unexplained liver or lung disease is present.

There is a large number of variants, Z and S are the most common variants. MM is the usual phenotype. Emphysema occurs in 70 – 90 % of patients with ZZ phenotype, as early as the 3rd or 4th decade, approximately 10% will have liver disease. Neonatal cholestasis is seen in 10% of ZZ patients. Patients with SZ and SS phenotypes are also at increased risk for emphysema. It is not clear whether MZ patients do have a small increase in risk for lung or liver disease or no increase in risk. MS patients are considered healthy. All patients with A1AT variants should avoid smoking.