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234 PHYSICIAN ERROR IN TESTING FOR POSSIBLE IgA DEFICIENCY DURING SCREENING FOR CELIAC DISEASE KE McGowan1,3, ME Lyon2,3, JD Butzner1 We examined physician evaluation and management of IgA deficiency during celiac disease screening.
1Department of Pediatrics, 2Department of Pathology & Laboratory Medicine, 3Calgary Laboratory Services (CLS), University of Calgary, Calgary, Alberta
METHODS: Consecutive IgA-endomysial antibody (EMA) and serum IgA results were obtained from the CLS database over 17 months (March 2003-July 2004). Seronegative tests with IgA deficiency (IgA<0.1g/L) were cross-referenced to the pathology database to identify corresponding intestinal biopsies. Questionnaires were sent to ordering physicians regarding the management of seronegative patients with IgA deficiency with no record of biopsy.
RESULTS: Of the 9,533 patients tested, only 4,698 (49%) were screened for IgA deficiency. Among these, 39 tests indicated IgA deficiency in 35 (0.7%) patients (median age: 33.5 years, range: 2-69 y; 23 females). Only 19 (54%) IgA deficient patients were managed appropriately with either intestinal biopsy (17) or negative IgG-tissue transglutaminase (2). Three (18%) biopsies were diagnostic of celiac disease and nine (53%) displayed other gastrointestinal diagnoses. Only five (29%) had no pathological diagnosis. No further evaluation to exclude celiac disease was performed for the remaining 20 negative EMA tests in patients with IgA deficiency. Inappropriate management by physicians included failure to recognize that IgA deficiency caused an unreliable EMA result (6) or an unnecessary repeats of the test was performed (4). Administrative issues (patient or result lost) accounted for seven tests, one patient refused further evaluation and two questionnaires were not returned. In addition, two pediatric patients displayed a positive EMA despite IgA deficiency (IgA <0.04g/L). Both had biopsy proven celiac disease.
CONCLUSIONS: The association between celiac disease and IgA deficiency was under recognized by physicians. Ordering a total serum IgA when ordering IgA-based celiac serology was not carried out in one, half of celiac disease screens. In addition, inappropriate management by physicians frequently occurred when IgA deficiency was detected. Additional cases of celiac disease likely go undiagnosed because of inadequate evaluation and management of IgA deficient patients who undergo celiac disease screening.