Facilitating the laboratory diagnosis of α1-antitrypsin deficiency.

α(1)-Antitrypsin (AAT) deficiency leads to deterioration of the lungs that can be prevented with diagnosis and treatment. Isoelectric focusing (IEF) electrophoresis is the current biochemical gold standard for detecting AAT deficiency variants but involves complex interpretation. Variant AAT samples were collected over a 2-year period. Stability of AAT for phenotype determination was assessed in whole blood, dried blood spots, and dried serum spots. A compendium displaying 13 common and 5 rare AAT phenotypes was created, and a detailed methodology describing how to recognize AAT banding patterns and interpret a rare phenotype accompanied these visual data. AAT was stable for IEF phenotype analysis for at least 1 week in whole blood and for 24 hours on dried serum spots. In conclusion, a reference compendium of known AAT phenotypes was established that can serve as a resource for interpreting AAT phenotypes.