Gastric juice for the diagnosis of H pylori infection in patients on proton pump inhibitors

AIM:To determine the efficacy of gastric juice polymerase chain reaction (PCR) for the detection of Hpylon infection in comparison with histology and gastric antral biopsy PCR in patients on a proton pump inhibitor(PPI).METHODS:Eighty-five consecutive patients with dyspeptic symptoms were enrolled.Gastric biopsies for histology,PCR and gastric juice were collected at endoscopy for PCR of the H pylori urease C gene (ure C).Sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV),accuracy,positive and negative likelihood ratio for PCR of gastric juice for the H pylori ure C gene was compared to histology and gastric antral biopsy H pylori ure C PCR in patients with and without PPI.RESULTS:Gastric juice PCR was positive in 66 (78%)patients.Histology showed H pylori associated gastritis in 57 (67%).Gastric biopsy PCR was positive in 72 (85%).In patients not taking PPI,the sensitivity,specificity,PPV,NPV,accuracy and positive and negative likelihood ratio for gastric juice PCR were 89%,72%,91%,67%,90%,85%,3.1 and 0.1 respectively.In patients on PPI these values were 86%,100%%,100%,29%,86%,9.5 and 1.4,respectively.CONCLUSION:Gastric juice PCR for the diagnosis of H pylori infection has increased sensitivity compared to histology with PPI.The use of gastric juice PCR is recommended to confirm H pylori status in patients taking PPIs.