The accuracy of the Helicobacter pylori stool antigen test in diagnosing H-pylori in treated and untreated patients

Objective and design To evaluate the performance of the Helicobacter pylori stool antigen test (HpSA test) in detecting H. pylori infection and monito ring the effect of treatment. This was done in two separate studies using e ither a biopsy or the C-13-urea breath test based 'gold standard' (in untre ated and treated patients, respectively). Setting Endoscopy units of two general hospitals. Patients One hundred and twenty-eight dyspeptic patients undergoing endosco py in the first study. Sixty-five patients receiving anti-H. pylori treatme nt in the second study. Results Sensitivity and specificity in untreated patients were 96.3% and 81 .8%, respectively. Seven days after treatment, these figures were 20% and 9 5%, and 4 weeks after treatment they were 40% and 95%. Conclusion The HpSA test is accurate in untreated patients but fails in mon itoring treatment success, Eur J Gastroenterol Hepatol 13:383-386 (C) 2001 Lippincott Williams & Wilkins.