Celiac.com 07/21/2009 - Accurate blood tests have revolutionized celiac disease diagnosis. Recently, researchers K.E. Evans, A.R. Malloy, and D.A. Gorard set out to review requests for celiac blood testing at a district general hospital laboratory over a decade, to measure the volume of requests, identify their source of referral, and assess positivity rates, along with subsequent rates of duodenal biopsy and histological confirmation.

The team used laboratory databases to gather details of patients who requested celiac blood tests from 1997 to 2006. They then categorized the referrals inasto gastroenterology, general practice, and pediatrics and other specialities, while excluding duplicate requests.

The team gathered 9976 serological tests in all. From 1997 to 2006, testing requests increased from 302 to 1826. About two-thirds (66%) of requests were made for women. Tests done on children accounted for 14-25% of each year's total. During that same period, test requests made via general practitioner rose from 3.3% to 52%, while the percentage of positive test results fell from 5.7% to 2.6%.

The number of duodenal biopsies fell from 85% of seropositive patients in earlier part of the decade to about 75% of seropositive patients in latter part. Most non-biopsied seropositive patients had blood requested by general practitioners. In more than 9 out of 10 seropositive patients (91%), biopsy confirmed celiac disease.

The data show that, increasingly, most celiac blood tests are now requested by general practitioners, with twice as many women as men being tested.

Rising requests for blood tests but shrinking rates of positivity suggest that people are getting tested earlier, with fewer or less severe symptoms than in the past. Positive blood tests are often not confirmed histologically.

Also of note, most patients with celiac disease no longer show classical signs of malabsorption, so diagnosis is often delayed or never made. These days, most adults diagnosed with celiac disease increasingly show few or atypical symptoms.

Although duodenal or jejunal biopsy remains the gold standard for diagnosing celiac disease, the availability of easy, accurate blood tests has dramatically improved the diagnosis of celiac disease.

More accurate tests for IgA endomysial antibodies and IgA tissue transglutaminase antibodies have replaced less reliable immunoglobulin (Ig) G and IgA gliadin antibody tests, while sensitivity and specificity of Endomysial antibodies and IgA tissue transglutaminase antibody tests now exceeds 95%.

Still, doctors recommend biopsy confirmation of positive blood antibody tests, as biopsy of patients with positive blood tests, along with those suspected of having celiac but with negative blood, remains the most comprehensive way of diagnosing celiac disease.

Aliment Pharmacol Ther 29, 1137-1142

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