Evaluation of a new enzyme immunoassay for detecting Helicobacter pylori in feces: A prospective pilot study

OBJECTIVE: There is an increasing interest in noninvasive tests for detecti ng Helicobacter pylori (H. pylori) infection. Unlike serological and urea b reath tests, the possibility of searching for H. pylori in feces has been s carcely investigated. The aim of this prospective pilot study was to evalua te the usefulness of a new enzyme immunoassay for detecting H. pylori antig ens in feces, as a predictor of H. pylori status in the pre- and posttreatm ent settings. METHODS: One hundred and fifty-four symptomatic, anti-H. pylori untreated p atients (Group A) and 116 anti-H. pylori treated patients (Group B) underwe nt gastroscopy with biopsies of the antrum and corpus for histology (H) and rapid urease test (RUT). In the anti-H. pylori created group, a 13(C)-urea breath test (UBT) was also performed. In Group A, H. pylori status was def ined as positive or negative when both H and RUT gave concordant positive o r negative results. In Group B, the patients were considered eradicated if all three tests were negative. A stool specimen was collected from all pati ents the day after gastroscopy, and tested by using an enzyme immunoassay c ommercial kit for detecting H. pylori antigens in feces (HpSAT). RESULTS: Eighty-five patients in Group A (55%) and 44 in Group B (38%) were H. pylori infected. On the whole, HpSAT showed a sensitivity of 94% and sp ecificity of 86%. In Group A and Group B, sensitivity and specificity were 94% versus 93%, and 90% versus 82%, respectively (p < 0.05). CONCLUSIONS: HpSAT seems to be a reliable method for predicting H. pylori s tatus in anti-H. pylori untreated patients. Conversely, the test appears le ss suitable to evaluate the outcome of the eradicating treatment. Consequen tly, it is likely to be accepted for the primary diagnosis of H. pylori sta tus, particularly in dyspeptic young patients. (Am J Gastroenterol 1999;94: 1830-1833. (C) 1999 by Am. Coll. of Gastroenterology).