Helicobacter pylori Stool Antigen Test (HpSA) for the diagnosis of gastric infection

Objective: To determine the accuracy of Helicobacter pylori Stool Antigen test (HpSA), compared with endoscopic histopathology for the diagnosis of gastric Helicobecter pylori infection. Study Design: Cross-sectional study. Place and Duration of the Study: Medical Unit 11, Abbasi Shaheed Hospital, Karachi, from March 2003 to March 2004. Patients and Methods: A total of 50 patients underwent endoscopy for gastric antral mucosal tissue biopsy for histopathology of H.pylori and advised for HpSA. Patient's information including age, gender, past history, presenting signs and symptoms, results of HpSA and histopathology were recorded. Sensitivity analysis was performed to calculate sensitivity, specificity, and predictive values of HpSA. Results: Among 50 patients, 48% males and 52% females (M: F 1: 1.08), a total of 27 (54%) were true positive while 20 (40%) were true negative. Two patients were false negative and only one was false positive. Sensitivity of HpSA was, therefore, 93.1%, specificity 95% and positive and negative predictive values were 96.42% and 90.9% respectively. Conclusion: Helicobacter pylori stool antigen was an accurate and reliable test for the diagnosis of gastric H. pylori infection.