DIAGNOSTIC ACCURACY OF STOOL ANTIGEN TEST FOR HELICOBACTER PYLORI DIAGNOSIS AT GIMS HOSPITAL; GAMBAT

Abstract

Objective: To assess the diagnostic value of the stool antigen test for Helicobacter pylori (H pylori) infection compared to gastric biopsy histopathology (gold standard). Methods: It was a cross-sectional validation study done in the outpatient and inpatient Department of Medicine at GIMS Hospital, Gambat for duration of six months. The patients were consecutively sampled as non-probability sampling of 226 patients aged between 18–60 years who had peptic ulcer disease as a suspected diagnosis. Stool samples were analyzed for Helicobacter pylori antigen using an immunochromatographic assay and upper gastrointestinal endoscopy and gastric mucosal biopsy were performed. Histopathology was used as the reference standard. These SPVs, PPVs, NPVs and diagnostic accuracy were computed in SPSS 26.0. Results: The mean age was 41.7 ± 11.2 years, and 121 (53.5%) participants were male. Gastric biopsy was positive for Helicobacter pylori in 124 (54.9%) patients and the stool antigen test in 116 (51.3%) patients. The numbers of true-positive, of true-negative, of false-positive and of false-negative results were 94, 80, 22, and 30, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and overall diagnostic accuracy were 75.8%, 78.4%, 81.0%, 72.7% and 77.0%, respectively. Conclusion: Stool antigen test had moderate diagnostic performance and could be used as a good non-invasive test to detect Helicobacter pylori infection; however, negative or discordant results should be interpreted with caution when final diagnosis is needed in clinical practice.