Evaluation of particle gel immunoassays for the detection of severe immunoglobulin A deficiency and anti-human immunoglobulin A antibodies.

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Immunoglobulin A (IgA )-deficient patients with anti-IgA (Ab ) require transfusions using blood components with less than 0 .05 mg IgA /dL as they are known to be safe for these patients . Identification of severely IgA-deficient (IgA SD ) donors involved preliminary screening by the Ouchterlony double immunodiffusion assay followed by confirmatory testing at the required level of sensitivity for IgA and Ab at an external reference laboratory . Two in vitro particle gel immunoassays (ID -PaGIA IgA deficiency test and anti-IgA test ) were also evaluated for their suitability in identifying IgA SD individuals and determining their Ab status .Samples from 198 donors and 36 patients , subjected to confirmatory testing for IgA SD and Ab over a 2 -year period , were also evaluated using the ID -PaGIA kits .DiaMed test sensitivity and specificity for detection of IgA SD in donors was 98 % whereas for Ab , test sensitivity was 91 % at a specificity of 94 %. In patients , sensitivity was 94 % for IgA SD and 67 % for Ab , both tests at a specificity of 100 %.The ID -PaGIA IgA deficiency test was a sensitive and specific tool for identifying IgA SD donors or patients . Sensitivity of the Ab test was high for donors but reduced for patients and of high specificity in both groups . Further studies with patients are needed to confirm this latter observation . Implementation of these tests would make it possible to supply appropriate products from IgA SD donors to prevent anaphylactic transfusion reactions in patients .