Assessment of four rapid urease test systems for detection of Helicobacter pylori in gastric biopsy specimens.

An in vitro experiment and an in vivo clinical trial were both performed in order to assess the efficacy of four biopsy urease test systems, including one commercial kit, Temmler CUT test (Temmler Pharma, Marburg, Germany), for the rapid detection of Helicobacter pylori. We first evaluated four rapid urease test systems by inoculating bacterial suspensions of different concentrations into urea-containing media and observing the color change at room temperature. We found that the CUT test was superior in vitro to the other three urease test systems. As was expected, the lower the concentration of the inoculum, the slower was the color change and the fewer were the positive results noted. The minimal concentration of H. pylori for a positive urease test at 24 h was 1000-10,000 colony-forming units/ml in 1 drop of bacterial suspension inoculated. We then evaluated four biopsy urease test systems for the rapid diagnosis of H. pylori infection in antral and fundal mucosa biopsy specimens of 37 patients undergoing upper gastrointestinal endoscopy. All four test systems were 100% specific when compared with culture. In 69 culture-positive biopsy specimens, the CUT test was not only more sensitive (72%) than the other three systems (42%, 51%, and 45%, respectively), but also gave the fastest reaction by detecting more culture-positive biopsy specimens after 3 h of incubation at room temperature. The differences were statistically significant.