Pathology Handbook

Alpha-1 antitrypsin phenotyping

Clinical Indications

Further investigation of low  serum alpha-1 antitrypsin levels. Samples will be automatically referred by Clinical Biochemistry if serum levels are less than 1.3 g/L

Request Form

Request on ICE


Analysed by referral laboratory if specific criteria met.

Specific Criteria

If total a-1 antitrypsin has been measured samples are referred for phenotyping if the level is less than 1.3 g/l in adults under the age of 65 or <0.8 g/L over the age of 65. 

If low a-1 antitrypsin has been picked up as an incidental finding from electrophoresis a comment is added to the report asking for the requesting clinician to discuss this with the patient before phenotyping is carried out. 

Patients with a-1 antitrypsin levels between 0.5 and 1.0 g/L are probably carriers and may not require further investigation.

Turnaround Time

1 month


Serum in gold-top vacutainer


2 ml


Vacutainer gold top

Lab Handling

Aliquot and store at 4C

Sent to referral laboratory (St George's Hospital)

Causes for Rejection

Serum alpha-1 antitrypsin level greater than 1.3 g/L; unlabelled samples


Normal phenotype is MM

See laboratory report for interpretation of results