Comparison of stool antigen test with gastric biopsy for the detection of Helicobacter Pylori infection

Abstract

Objective: Helicobacter Pylori (H.pylori) is one of the most important causes of dyspepsia and diagnosis can be made by invasive or non-invasive methods. One of the non-invasive methods, H.pylori stool antigen test (HpSA) is simple, fast and relatively inexpensive. According to this view with regard to gastric biopsy as a gold standard the sensitivity, specificity, positive and negative predictive values of this method were calculated.

Methodology: Stool samples of 61 patients who underwent upper endoscopy and gastric biopsy due to dyspepsia were evaluated for H. Pylori stool antigen using sandwich ELISA method.

Results: From the 61 patients who participated in this study, H.pylori was diagnosed in 38 (62.3%) gastric biopsies, 25(66%) of these had positive HpSA test. Also, of 27 (37.7%) positive HpSA cases, H.pylori was seen in 25 gastric biopsies. For this method, sensitivity of 66% with 93% positive predictive value was calculated. Also, 91% specificity with 62% negative predictive value was estimated.

Conclusion: High positive HpSA indicates high risk of H.pylori infection and high specificity shows that the likelihood of false positive is low. Therefore, physicians can trust on this method and start patient`s treatment.

Keywords: Dyspepsia; Gastric biopsy; Helicobacter Pylori stool antigen; Negative predictive value; Sensitivity; Specificity.