Validation of a new, commercially available dry rapid urease test for the diagnosis of Helicobacter pylori infection in gastric biopsies.

BACKGROUND: To compare the accuracy and reaction time of a new dry rapid urease test (GUT test) with the CLO test and an independent gold standard in the diagnosis of Helicobacter pylori infection. To determine whether this new test can replace the CLO test in routine clinical practice. METHODS: We included consecutive patients in whom normal-sized gastric biopsies were taken in routine practice. six antral and three corpus biopsies were taken for determination of H. pylori infection. results of the GUT test were monitored after 15, 60 and 120 minutes of incubation. Results were compared with the standard CLO test and an independent gold standard (bacterial culture and histology). The results of the CLO test were also compared with the gold standard. RESULTS: 116 patients were recruited in the study: 60 were males and 56 females. The mean age was 59.3 years (range 14-89 years). Compared with the CLO test, the GUT test had a sensitivity of 76.7% and a specificity of 100% in 15 minutes. After 60 minutes the sensitivity of the GUT test increased to 95.3%, the specificity remained 100%. All positive results of the GUT test occurred before 60 minutes of incubation. Compared with the gold standard, the GUT test had a sensitivity and specificity of 97.4 and 96.1% respectively. The CLO test had a sensitivity of 97.4% and a specificity of 93.5%, when compared with the gold standard. CONCLUSION: The GUT test appeared to be a good and reliable alternative for the widely used Clo test in diagnosing H. pylori infection. The GUT test results were not yet reliable after 15 minutes, but all positive results occurred before 60 minutes of incubation. The test can best be read 60 to 120 minutes after endoscopy.