An evaluation of the DiaMed assays for immunoglobulin A antibodies (anti-IgA) and IgA deficiency

BACKGROUND: Immunoglobulin A antibodies (anti-IgA) are rare but can cause transfusion-associated anaphylaxis. The detection of anti-IgA has traditionally been performed using a labor-intensive hemagglutination assay in a limited number of reference laboratories. STUDY DESIGN AND METHODS: Two simple gel card assays are now available that can be used to screen for anti-IgA and IgA deficiency. A total of 24 serum samples that had been previously assayed for anti-IgA over a 3-year period were used to assess the DiaMed anti-IgA and IgA deficiency assays. RESULTS: The DiaMed assays correctly identified patients (n = 6) who had significant IgA deficiency and anti-IgA. All patients with an abnormal anti-IgA titer by hemagglutination assay and who were also IgA-deficient had anti-IgA detected using the DiaMed screening test. One patient, previously shown to have an IgA level of less than 0.067 g per L, failed to be detected as IgA-deficient in the DiaMed IgA deficiency test; however, anti-IgA were not present. Samples with slightly increased anti-IgA titers tended to have normal IgA levels. CONCLUSION: The DiaMed gel card screening assays are appropriate screening tools for the investigation of transfusion-related anaphylactic reactions and can be used in any routine blood bank laboratory.