Diagnostic Testing for CD
For CD, serum IgA endomysial antibodies (EMA) and tissue transglutaminase (tTG) antibody testing have the highest diagnostic accuracy. Immunoglobulin A (IgA) anti-tTG antibody testing is the preferred method for detection of CD in individuals over the age of 2 years. Positive celiac serologic testing on a gluten-containing diet and endoscopy with duodenal biopsy with villous atrophy consistent with CD will confirm the diagnosis of CD. For NPs, it is important to emphasize to patients that they must be ingesting gluten to test for CD. If a patient has started a gluten-free diet on their own for several weeks before testing, then the tests to diagnose CD may be negative and unreliable. If CD is still suspected, a gluten challenge may be done and tests repeated. For CD, the classic gluten challenge has been to consume at least 10 g of gluten (the equivalent of 4 slices of bread) per day for 6 to 8 weeks,[5,18] but a recent CD study suggested the gluten challenge may be shortened to 2 weeks with doses of 3 grams (1 slice of bread) per day.
Journal for Nurse Practitioners. 2014;10(9):666-673. © 2014 Elsevier Science, Inc.