A comparison of new rapid urease tests for detection of Helicobacter pylori: test characteristics and factors affecting positivity and time to positivity.

Abstract

We assessed two new rapid urease tests, the Helicobacter Urease Test (HUT, Astra, Sweden) and the Polish test, for accuracy, reaction time, and the effect of biopsy site and bacterial density on test characteristics and time to positivity. A prospective study was conducted in two groups of patients: 64 consecutive patients undergoing upper endoscopy for dyspepsia and 61 consecutive patients with duodenal ulcer on upper endoscopy. In the first group, test accuracy, time to positivity, and possible associations with biopsy site and bacterial density were assessed between the tests. In the second group, the two new tests were compared with the CLOtest for time to positivity and effect of bacterial density on test outcome. The Polish and HUT test had similar specificities (97%), but the Polish test was more sensitive (90.3% vs. 80.7%). The Polish test was positive within 10 minutes in 55% of the positive patients compared with 10% for the HUT test. There was no association between bacterial density (by histologic count) and reaction time in either test or in the CLOtest in the second group. The Polish test was more accurate and had a quicker time interval to positivity than the HUT. There was no significant association between bacterial density and reaction time in any of the urease tests assessed, and the biopsy site did not affect test accuracy in the HUT test.