TOPLINE:
Adults with suspected celiac disease and no immunoglobulin A (IgA) deficiency most likely can avoid a diagnostic bowel biopsy if they have high serum anti-tissue transglutaminase IgA (tTG-IgA).
METHODOLOGY:
Researchers evaluated the reliability of serum tests for diagnosing celiac disease, as defined by duodenal villous atrophy (Marsh type 3 or Corazza–Villanacci grade B).
The main study cohort included 436 adults with suspected celiac disease who did not have IgA deficiency and who were not on a gluten-free diet (mean age, 40 years; 68% women). The patients were referred by 14 centers across four continents to undergo local endoscopic duodenal biopsy.
Local serum tTG-IgA was measured with 14 test brands. Concentration was expressed as a multiple of each test's upper limit of normal (ULN). Tests were defined as positive when they exceeded 1 times the ULN.
Histology was assessed by the local pathologist, and discordant cases were reevaluated by a central pathologist.
TAKEAWAY:
Positive serum tTG-IgA was detected in 363 (83%) participants; negative serum tTG-IgA was detected in 73 (17%).
After local review, 341 of the participants with positive serum tTG-IgA had positive histology (true positives) and 22 had negative histology (false positives).
Of the 73 participants with negative serum tTG-IgA, 66 had negative histology (true negatives) and seven had positive histology (false negatives).
