Adult patient:
Heparin gel tube
Minimum blood volume: 5 mL
Paediatric heparin tube
Number of vials: 1
Minimum blood volume: 1.3 mL
Authorisation code required
No
24 Hr available service
Yes
(Call extension: 3353 for express result)
Method
Immunoassay
Reference interval
0.90 - 2.00 g/L
(Source: from manufacturer's kit insert)
Clinical indication
Detection of hereditary deficiency
Investigation of early onset emphysema; neonatal hepatitis; juvenile cirrhosis; panniculitis
Result interpretation
α1-antitrypsin deficiency is associated with early onset emphysema, hepatitis and cirrhosis and with panniculitis. If deficiency is documented, phenotyping should be done on proband and family.
Levels of α1-antitrypsin are increased in an acute phase response and this may mask a deficiency state; if there is a high clinical suspicion of α1-antitrypsin deficiency, phenotyping should be performed, regardless of the α1-antitrypsin level.
Genetic variants with at least 100 alleles have been described; genotyping is currently available for two phenotypes associated with disease: S and Z.
Genotyping is currently not the preferred first line test but may be used to distinguish ZZ from Z null or SS from S null patients without the need for family studies.
Measurement of uncertainty
Frequency of measurement
Daily