Screening of blood donors for IgA deficiency: a study of the donor population of south-west England.

Altogether 29 745 English blood donors were screened for IgA deficiency by double diffusion analysis; 57 had apparent absence of IgA, a frequency of 1:522. Further examination by the more sensitive haemagglutination inhibition assay revealed 34 samples having no detectable IgA, a frequency of 1:875. All donors negative by double diffusion analysis were tested for the presence of antibodies to IgA. Six class specific anti IgA antibodies and four anti IgA antibodies of limited specificity were detected. Three of these had the specificity anti alpha2 and one anti A2m(2). The 34 IgA deficient donors detected provide a source of IgA deficient blood for transfusion to patients with anti IgA antibodies.