Typing of genetic variants of alpha 1-antitrypsin from dried blood

The alpha 1-antitrypsin phenotype was determined from both plasma and dried blood in 35 children and adolescents who had or were suspected to have alpha 1-antitrypsin deficiency. A disc of paper with dried blood was eluted and analysed by flat bed electrofocusing on polyacrylamide gel. The gel was stained according to a silver-staining technique until the microheterogeneous bands appeared with adequate intensity. The alpha 1-antitrypsin patterns of plasma and dried blood were identical. The stability of the dried blood samples was 3 days at room temperature, up to 1 week at +4 degrees C, and up to 1 month at -20 degrees C. The alpha 1-antitrypsin screening method and the Pi-typing procedure described in this study may be combined in future screening studies using dried blood specimens obtained for the Guthrie test.