Point-of-care testing for celiac disease has a low sensitivity in endoscopy

Abstract

Background: Celiac disease (CD) is a common but underdiagnosed condition. A rapid point-of-care test (POCT) could reduce lead times and missed diagnoses.

Objective: To assess the utility of an immunoglobulin (Ig) A tissue transglutaminase (TTG) antibody POCT in an endoscopic setting.

Design: Prospective observational study.

Setting: A single UK university hospital.

Patients: Patients presenting with suspected CD, known CD, and routine endoscopy for upper GI symptoms.

Interventions: All patients were tested with POCT, serum TTG, endomysial antibody (EMA), and upper GI endoscopy with duodenal biopsies at the same visit.

Main outcome measurements: Comparison was made with histology in all cases, with villous atrophy regarded as diagnostic of CD.

Results: A total of 576 patients (63.5% female, mean [± standard deviation] age 49.7 years [± 17.6 years]) were recruited. A total of 523 patients had no prior diagnosis of CD, and 53 patients had known CD coming for reassessment. A total of 117 patients were newly diagnosed with CD, and 82 were positively identified by the POCT. Sensitivity, specificity, positive predictive value, and negative predictive value were 70.1%, 96.6%, 85.4%, and 91.8%, respectively. In comparison, TTG and EMA both performed significantly better than the POCT. Sensitivity and specificity of TTG were 91.0% and 83.5%, respectively, and EMA were 83.8% and 97.5%, respectively. Of patients with known CD coming for reassessment, 26 had villous atrophy, and POCT results were positive in 16 (61.5%). There was poor agreement between POCT and standard serology.

Limitations: High pre-test probability of CD.

Conclusion: The performance of this POCT was disappointing compared with standard serology and cannot at present be recommended within the context of an endoscopy unit.