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.


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.


CONCLUSIONS
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.
Brown
Ross
R
From the Institute of Haematology and Blood Bank Laboratory, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia. ross.brown@email.cs.nsw.gov.au
Nelson
Margaret
M
Aklilu
Esther
E
Kabani
Karieshma
K
Yang
Shihong
S
Blayney
Bernadette
B
Popp
Hazel
H
D000707:Anaphylaxis / Q000517:prevention & control; D000888:Antibodies, Anti-Idiotypic / Q000032:analysis / Q000097:blood*; D006801:Humans; D017098:IgA Deficiency / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D007118:Immunoassay / Q000592:standards*; D008403:Mass Screening / Q000592:standards; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012016:Reference Values; D015203:Reproducibility of Results; D065227:Transfusion Reaction
D000888:Antibodies, Anti-Idiotypic; D011933:Reagent Kits, Diagnostic; C049937:anti-IgA