Alpha-1 Antitrypsin Phenotyping: An Unmet Educational Need of Healthcare Providers

Diagnosing alpha-1 antitrypsin deficiency (A1ATD) involves two-step laboratory testing, determination of serum alpha-1 antitrypsin (A1AT) level and phenotyping if A1AT < 100 mg/dL. Whether these guidelines are effectuated in clinical practice is uncertain. To begin to address this issue, we determined whether A1AT phenotyping is performed in patients with serum A1AT 57 - 99 mg/dL at our institution.

We reviewed the medical records of patients seen at Jesse Brown Veterans Affairs Medical Center from January 2019 to October 2022 with serum A1AT between 57 and 99 mg/dL. In each case, pertinent demographic, clinical, and pulmonary function tests data were extracted. Data were presented as means and standard deviation (SD) where appropriate. The Student's t-test was used for statistical analysis. P < 0.05 was considered statistically significant.

Thirty patients (90% males; 60 ± 18 years) with serum A1ATD < 100 mg/mL were identified. Fourteen were African Americans, four Hispanics, and 12 non-Hispanic Whites. The majority were current or ex-smokers. Fourteen (47%) patients had lung disease, 14 (47%) liver disease and one had concomitant lung and liver diseases. Mean ± SD forced expiratory volume in 1 s (FEV₁) and lung diffusing capacity were 2.57 ± 1.41 L (67±19% predicated) and 18.7 ± 10 mL/min/mm Hg (64±28% predicted), respectively. Only 13 patients (43%) underwent phenotype testing (seven African Americans, five Whites, and one Hispanic). Six patients had MZ phenotype, four MS, and three SZ. One patient died from acute respiratory failure during the study period.

Phenotyping of patients with serum A1AT 57 - 99 mg/dL at our institution is inadequate. Accordingly, regular continuous medical educational programs on A1AT phenotyping targeting healthcare providers are warranted.