A protocol for sensitive large-scale screening of blood donors for IgA deficiency.

A protocol for large-scale screening of blood donors for IgA deficiency using a tanned cell passive haemagglutination-inhibition (PHI) technique and enzyme-linked immunosorbent assay (ELISA) is described. Evidence presented suggests that native serum from a case of IgA paraproteinaemia, suitably diluted and heated to 56 degrees C for 60 min, can act as a satisfactory and simple alternative to purified IgA preparations in the PHI test. When PHI and ELISA techniques were used in combination to screen 41,851 random donors, 58 were found to contain less than 200 ng/ml of IgA and were classified as totally IgA-deficient (1:721). This is in close agreement with the data from other workers.