Celiac disease serology in patients with different pretest probabilities: is biopsy avoidable?

AIM: To establish the diagnostic performance of several serological tests, individually and in combination, for diagnosing celiac disease (CD) in patients with different pretest probabilities, and to explore potential serological algorithms to reduce the necessity for biopsy. METHODS: We prospectively performed duodenal biopsy and serology in 679 adults who had either high risk (n = 161) or low risk (n = 518) for CD. Blood samples were tested using six assays (enzyme-linked immunosorbent assay) that detected antibodies to tissue transglutaminase (tTG) and deamidated gliadin peptide (DGP). RESULTS: CD prevalence was 39.1% in the high-risk population and 3.3% in the low-risk group. In high-risk patients, all individual assays had a high diagnostic efficacy [area under receiving operator characteristic curves (AU ROC): 0.968 to 0.999]. In contrast, assays had a lower diagnostic efficacy (AU ROC: 0.835 to 0.972) in the low-risk group. Using assay combinations, it would be possible to reach or rule out diagnosis of CD without biopsy in 92% of cases in both pretest populations. We observed that the new DGP/tTG Screen assay resulted in a surplus compared to more conventional assays in any clinical situation. CONCLUSION: The DGP/tTG Screen assay could be considered as the best initial test for CD. Combinations of two tests, including a DGP/tTG Screen, might be able to diagnose CD accurately in different clinical scenarios making biopsy avoidable in a high proportion of subjects.

A prospective evaluation of endoscopic markers for identifying celiac disease in patients with high and low probability of having the disease.

BACKGROUND/OBJECTIVES: the usefulness of duodenoscopic markers for predicting celiac disease (CD) has been questioned. We assessed the diagnostic efficacy of endoscopic markers of mucosal atrophy in individuals with different pretest probability of CD. METHODS: we prospectively performed endoscopic intestinal biopsies and CD-related serology tests in 661 individuals, including 143 consecutive patients attending a malabsorption clinic (high pretest probability) and 518 subjects randomly selected fom those undergoing routine endoscopy because of upper GI symptoms (low pretest probability). Duodenoscopic markers reported were: mosaic pattern, scalloped folds, and reduction in number or loss of Kerkring's folds. RESULTS: sixty-three (44.1%) and 18 (3.5%) patients were diagnosed with CD in the high and low risk groups, respectively Among high pretest subjects, the presence of any marker had very high sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for the identification of CD (92.1%, 93.8%, 92.1%, 93.8% and 93.0%, respectively). The performance of these parameters for the presence of any marker in the low pretest population were 61.1%, 96.8%, 40.7%, 98.6% and 95.6%, respectively. Sensitivity (p < 0.004) and positive predictive value (p < 0.0001) of markers were significantly higher for the high risk patients. The identification of a reduction in number or loss of Kerkring'sfolds was not a reliable finding unless other signs were also present. CONCLUSIONS: we confirm that endoscopic markers are useful in predicting CD in different clinical scenarios. The high negative predictive value in the low probability group suggests that intestinal biopsy is not required if endoscopic markers are absent.