Validation in China of a non‐invasive salivary pepsin biomarker containing two unique human pepsin monoclonal antibodies to diagnose gastroesophageal reflux disease

Objectives Peptest is a new non‐invasive reflux diagnostic test based on lateral flow technology that containing two highly specific human pepsin monoclonal antibodies for detecting pepsin, a biomarker for reflux disease. The primary aim of this multicenter clinical study was to validate the efficacy of Peptest in patients diagnosed with gastroesophageal reflux and healthy controls in China. Methods Patients with suspected gastroesophageal reflux underwent an endoscopy and were classified into non‐erosive reflux disease and erosive esophagitis subgroups. A healthy control group was also recruited. All participants were given a reflux disease questionnaire—patients scoring greater than 12 and controls scoring zero. All participants provided a postprandial saliva sample and most patients gave an additional post‐symptom sample for pepsin analysis. Results Altogether 1032 participants aged between 19 and 78 years were recruited. They consisted of 488 patients with non‐erosive reflux disease, 221 with erosive esophagitis and 323 healthy controls. The number of postprandial and post‐symptom samples analyzed totaled 1031 and 692, respectively. The results across all centers showed an overall pepsin‐positive sensitivity of 85%, a specificity of 60%, a positive predictive value of 82%, a negative predictive value of 65% and a positive likelihood ratio of 2.12. Conclusion The sensitivity of Peptest was high, but the specificity achieved in some centers was low, resulting overall in only a moderate specificity. Further diagnostic investigative studies are warranted.