Diagnostic Testing for CD
For CD, serum IgA endomysial antibodies (EMA) and tissue transglutaminase (tTG) antibody testing have the highest diagnostic accuracy.[17] Immunoglobulin A (IgA) anti-tTG antibody testing is the preferred method for detection of CD in individuals over the age of 2 years.[5] 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.[5] 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.[19]
Journal for Nurse Practitioners. 2014;10(9):666-673. © 2014 Elsevier Science, Inc.