Quantitative testing: determining serum alpha1-antitrypsin (AAT) protein levels1,6
The normal level of serum AAT protein is 20 µM and above.1,3
Lower levels of circulating AAT indicate a risk of alpha1-antitrypsin deficiency (AATD) and
emphysema.1,3,7
The theoretical protective threshold level of AAT is 11 µM; below this, patients may be at an increased risk of developing emphysema.1
Given AAT is an acute phase reactant, its serum levels can be affected by inflammation, pregnancy and vaccinations, and therefore should be evaluated when the patient is clinically stable.4
Quantitative test results indicating an individual has a low serum AAT level should be corroborated by qualitative testing to detect the AAT variant present and to determine the individual's genotype.1,7
