Optimal alpha-1 antitrypsin level cutoffs for genotype identification in patients with chronic liver disease

Abstract

Background:. Controversy exists whether alpha-1 antitrypsin (A1AT) genotype testing should be performed as a first-line screening for A1AT heterozygous variants. Methods:. We calculated the median and interquartile range of A1AT level for each genotype in 4378 patients with chronic liver disease and “miss rate” of MZ genotype identification at various cutoff levels. Findings:. Significant overlap in A1AT level noted with Pi*MM, MZ, and MS variants. Miss rate of Pi*MZ at a cutoff level <100 was 29%, <110 was 18%, <120 was 8%, and <130 was 4%. We suggest simultaneous measurement of A1AT level and genotype in patients with chronic liver disease.