Alpha-1 Antitrypsin (AAT)

Immunology

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Description

Alpha-1 antitrypsin ( AAT ) is a 54 kDa glycoprotein. This proteolytic inhibitor has a wide range of inhibitory activities, in particular against inflammatory cell enzymes such as elastase. The quantitation of AAT is indicated in the evaluation of chronic obstructive airway disease, emphysema and in neonatal and adult liver disease where low concentrations may have diagnostic importance [1,2]. AAT deficiency is an inherited autosomal co-dominant disorder in which over 100 alleles have been identified. It has an incidence of 1 in 2000-5000 individuals. The Z and S alleles are the most frequent AAT deficiency alleles [2,3]. Allele frequencies vary between different populations. Genetic counselling should be offered to all heterozygote individuals, Z carriers and their respective partners [1,3]. An association between C-ANCA positive vasculitis and alpha-1 antitrypsin deficiency has also been recorded [4].

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Indications

Used for the investigation of Emphysema / cirrhosis / family screen / prolonged neonatal jaundice.

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Sample Type

2mL Serum ( Gel 5mL Yellow tube ). Requests from outside Sheffield: Transport at ambient temperature via Royal Mail or Courier.

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Reference Range

Age | 5th centile | 95th centile
Birth | 0.9 | 2.2
6 months | 0.8 | 1.8
1 year | 1.1 | 2.0
5 years | 1.1 | 2.2
10 years | 1.4 | 2.3
15 years | 1.2 | 2.0
Adult | 1.1 | 2.1

The 5th-95th centile ranges are for normal individuals.

Reference ranges established in house and with PRU collaboration.

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Turnaround Time

Within 2 days

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Testing Frequency

Daily

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References

PRU Handbook of Clinical Immunochemistry. 9th Edition. 2007. [Ref 1]
Stoller JK, Aboussouan LS. Alpha-1 antitrypsin deficiency. Lancet. 2005. 365: 2225-2236. [Ref 2]
M Luisetti and N Seersholm. Alpha-1 Antitrypsin deficiency.1: Epidemiology of alpha-1 antitrypsin deficiency. Thorax. 2004. 59:164-169. [Ref 3]
American Thoracic Society/ European Respiratory Society. Standards for the diagnosis and management of individuals with alpha-1 antitrypsin deficiency. Am J Respir Crit Care Med. 2003. 168:818-900.
Barnett T, et al. Wegener's Granulomatosis and alpha-1 antitrypsin deficiency emphysema - proteinase related diseases. Chest. 1999. 116:253-255. [Ref 4]

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See Also

AAT Genotype; AAT Phenotype

Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.