Frequency of IgA deficiency in blood donors and Rh negative women in Iceland.

Sera from 6,842 individuals were tested for IgA deficiency, using double and radial immunodiffusion. Sera containing less than 1 mg/100 ml of IgA were classified as deficient. The frequency of selective IgA deficiency among 4,799 blood donors investigated was 1:533, but 1:340 among 1,017 Rh negative women screened and 1:485 for both groups combined. One of the nine IgA deficient blood donors detected belonged to a 1st cousin marriage family previously investigated, in which the mother also was deficient in IgA. One IgA deficient recipient was found among 704 hospital patients screened for this abnormality.