Alpha-1 antitrypsin deficiency: a commonly overlooked cause of lung disease

Typical ranges of serum alpha-1 antitrypsin levels for different genotypes (normal, heterozygous carriers of alpha-1 antitrypsin deficiency and homozygous deficiency). The left axis is expressed in μM because this unit is common in the literature. The right axis shows an approximate conversion into mg/dL because this unit is commonly reported by clinical laboratories and by different measurement technology (nephelometry or radial immunodiffusion). Adapted from Brantly and colleagues17 and the American Thoracic Society/European Respiratory Society statement.9 Note: AAT = alpha-1 antitrypsin.