IgA Deficiency Is Not Systematically Ruled Out in Patients Undergoing Celiac Disease Testing

Background Guidelines for celiac disease (CD) testing recommend total serum IgA determination alongside anti-transglutaminase IgA antibodies. It is not well known if lack of serum IgA determination is a common finding in clinical practice. Aim To determine the prevalence of lack of serum IgA determination among patients screened for celiac disease. Materials and Methods We identified all subjects who underwent serum anti-transglutaminase IgA and/or other CD-related antibodies determination at a single teaching hospital in Buenos Aires from October 2019 to February 2020. Medical records were reviewed to select adult patients who were tested for celiac disease. The primary outcome was the proportion of patients with inadequate testing for celiac disease due to lack of serum IgA determination. We retrieved the following variables from each patient’s record: age, gender, body mass index, symptoms present at screening, first-grade family history of CD, history of type-1 diabetes mellitus, autoimmune hypothyroidism, Down’s syndrome. Results Overall, 1122 patients were included for analysis. Lack of serum IgA determination prevalence was 20.49%. Among patients who did have serum IgA determination, the prevalence of IgA deficiency was 5.16%. The following variables were independently associated with a significantly increased odds of serum IgA determination: diarrhea [OR 1.55 (1.01–2.34)] and abdominal pain [OR 2.28 (1.44–3.63)]; higher body mass index [OR 0.91 (0.85–0.98)], osteoporosis [OR 0.49 (0.28–0.89)], hypothyroidism [OR 0.18 (0.07–0.45)], arthralgia/arthritis [OR 0.47 (0.27–0.85)], or testing by endocrinologist [OR 0.46 (0.23–0.91)] and gynecologist [OR 0.14 (0.06–0.31)] were inversely associated. Conclusion IgA deficiency is not systematically ruled out in a relatively high proportion of patients undergoing serological screening of celiac disease.