Low Sensitivity of Simtomax Point of Care Test in Detection of Celiac Disease in a Prospective Multicenter Study

Abstract

Background & aims: Point of care tests (POCTs) might be used to identify patients with undiagnosed celiac disease who require further evaluation. We performed a large multicenter study to determine the performance of a POCT for celiac disease and assessed celiac disease prevalence in endoscopy centers.

Methods: We performed a prospective study of 1055 patients (888 adults; median age, 48 yrs and 167 children; median age, 10 yrs) referred to 8 endoscopy centers in Germany, for various indications, from January 2016 through June 2017. Patients were tested for celiac disease using Simtomax, which detects immunoglobulin (Ig)A and IgG antibodies against deamidated gliadin peptides (DGP). Results were compared with findings from histologic analyses of duodenal biopsies (reference standard). The primary aim was to determine the accuracy of this POCT for the detection of celiac disease, to identify candidates for duodenal biopsy. A secondary aim was to determine the prevalence of celiac disease in adult and pediatric populations referred for outpatient endoscopic evaluation.

Results: The overall prevalence of celiac disease was 4.1%. The POCT identified individuals with celiac disease with 79% sensitivity (95% CI, 64%-89%) and 94% specificity (95% CI, 93%-96%). Positive and negative predictive values were 37% and 99%. When we analyzed the adult and pediatric populations separately, we found the test to identify adults with celiac disease (prevalence 1.2%) with 100% sensitivity and 95% specificity. In the pediatric population (celiac disease prevalence 19.6%), the test produced false-negative results for 9 cases; the test therefore identified children with celiac disease with 72% sensitivity (95% CI 53%-86%). Analyses of serologic data revealed significantly lower DGP titers in the false-negative vs the true-positive group.

Conclusions: In a study of more than 1000 adults and children, we found the Simtomax POCT to detect celiac disease with lower overall levels of sensitivity than expected. Although the test identifies adults with celiac disease with high levels of sensitivity and specificity, the prevalence of celiac disease was as low as 1.2% among adults. The test's lack of sensitivity might be due to the low intensity of the POCT bands and was associated with low serum DGP titers. Study ID no: DRKS00012499.

Keywords: Diagnostic; Gastroscopy; Gluten; Noninvasive.