Identifying immunoglobulin-A--deficient children and adults does not necessarily help the serologic diagnosis of coeliac disease.

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Immunoglobulin A deficiency is more common in patients with coeliac disease and also in patients with other gastrointestinal diseases than in normal people . There is a concern , therefore , that routine serum immunoglobulin (Ig ) A testing of all cases of suspected coeliac disease may lead to unnecessary biopsy .Four hundred eighty-two routine consecutive samples from cases of suspected coeliac disease or malabsorption (109 children ) were tested for IgA anti-endomysium and total IgA . Four hundred twenty-four sera samples also had IgG antigliadin checked for high -titre antibody . Archived adult sera from 31 patients with coeliac disease and 52 disease control subjects were included in the study .Seven routine cases with serum IgA less than 15 % of the mean normal for age and four cases with undetectable IgA were identified . Four patients , including three of four with clear deficiency , underwent small bowel biopsy , and all four had normal histologic findings and normal intraepithelial lymphocyte counts . Only one of the seven had high -titre IgG antigliadin antibody but that patient had normal histologic findings . One (3 %) of 31 adults with established coeliac disease and 1 (2 %) of 52 control subjects were IgA deficient .Of patients with IgA deficiency , only those with both IgA deficiency and high -titre IgG antigliadin antibody should be routinely considered for biopsy .