Preferred Sample Type

Alpha-1-Antitrypsin (A1AT or AAT)

Suitable Specimen Types

  • Serum
  • EDTA Plasma
  • Li Hep Plasma
0.5 mL blood (1 x paed EDTA tube)

Specimen Transport

Not applicable

Sample Processing in Laboratory

No special transport requirements

Sample Preparation

Centrifuge. Store at 4oC

Turnaround Time

2 days

Sample Stability

4 ºC (stable for 7 days at 4oC)

Alpha-1-Antitrypsin (A1AT or AAT)

General Information

Alpha-1-Antitrypsin is a glycoprotein synthesised in hepatocytes and is quantitatively the most important proteinase inhibitor (Pi) in serum and plasma. It specifically inactivates serine proteases (eg. Trypsin, chymotrypsin, collagenase, leucocyte elastase, plasmin and thrombin) with which it reversibly forms an enzyme-indicator complex.

Acute hereditary alpha-1-Antitrypsin deficiency is suspected in cases of neonatal hepatitis accompanied by progressive liver cirrhosis in early childhood. It is also suspected when severe pulmonary emphysema occurs in adults due to the prevalence of leucocyte elastase, which can lead to unrestrained proteolytic degradation of the pulmonary parenchymal cells.

Genetic variants of A1AT are characterised by their different electrophoretic mobilties i.e. M, S or Z. Z and S variants have decreased synthesis of A1AT. S forms produce 60-80% of normal and Z produces only 15% of normal.Normal range is age related.

Patient Preparation



No significant interference from haemolysis, icterus, or lipaemia. Elevated oestrogen levels (oral contraceptives, 3rd trimester of pregnancy) give rise to false positive results

Reference Range

Adult range 1.1 - 2.1 g/L.

Age related ranges are available by contacting the Immunology department.


  • EQA Scheme?: Yes
  • EQA Status:

    UK NEQAS for Specific Proteins scheme

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The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235