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.

The Evaluation of Diagnostic and Predictive Values of Helicobacter pylori Stool Antigen Test in Iranian Patients with Dyspepsia

“…Consistent with the former studies (16,(19)(20)(21)(22)(23)(24)(25), the current study found that HpSA test was sensitive, specific, and accurate to diagnose Hp infection (sensitivity: 80.4%, specificity: 85.7%). To avoid false negative results, which would be achieved if there was a history of chronic liver diseases (eg, cirrhosis), gastrointestinal bleeding, and antacid medications, the patients undergoing proton pump inhibitor or bismuth therapy were excluded.…”

Role of Helicobacter Pylori stool antigen test in the diagnosis of Helicobacter Pylori infection

“…The diagnostic values for HpSA in the study of Sharbatdaran et al 17 using polyclonal technique were 66%, 93%, 91% and 62%, respectively. Syam et al 21 also observed that HpSA when using polyclonal technique has sensitivity of 66.7% and specificity of 78.9%.…”

“…1 There are studies evaluating the accuracy of HpSA for detection of H. pylori in children 14,15 and hemodialysis patients, 12,16 but studies about HpSA accuracy in adults with GI complaints in Iran are few. 10,11, 17 Here, we examined the role of HpSA in diagnosing H. pylori infection in patients with upper GI complaints. In this prospective study, H. pylori infection was evaluated using HpSA in patients with upper GI complaints undergoing diagnostic endoscopy.…”

Histological Interpretation of Helicobacter pylori Density Relevant to Gastric Pathology and its Bias

“…Anyway, precipitates or striae of mucous covering without regular bacterial contour, and neither gray staining for H & E stain nor dark blue staining for Giemsa stain should not be interpreted as low or trace HP density. Otherwise, these over interpretations of so called gold standard might reflect in appropriate lower sensitivity of other HP tests such as stool antigen test in some nations [16,17] comparing with that of another nation [18]. More expensive HP Immunohistochemical (IHC) stain can reduce false positive or false negative results dramatically [19].…”