This study was aimed to assess the value of rapid urease test (CLO test) for thedetection of Helicobacter (H.) pylori in patiens with duodenal ulcer and compare its resultwith histological technique using H & E stain.

The CLO test and histological study were done using three pieces of antral biopsyspecimens in 46 patients with duodenal ulcer. The clinical histories such as smoking, bloodtype or the previous use of NSAIDs were obtained from the patients.

1) The CLO test was positive in 35 (76.1%) among 46 patients with duodenal ulcer, while H & E stain was positive in 91.3%.

2) When H & E stain positive case was diagnosed as H. pylori infection, the sensitivity of CLO test was 81.0%, the specificitry 75.0% and the predictability was 97.1%.

3) The grading of gastric inflammation showed that the higher the histologogical grade, the more likely CLO test would be positive.

4) There were no differences of recurring history of duodenal ulcer, smoking rate, NSAIDs history and blood type between 34 cases of both CLO and H & E positive cases and 3 cases ofboth negative cases except a mild increasing tendency of age, male predominance and scarringstage of duodenal ulcer in both negative cases.

The CLO test is a rapid and simple test, but it should require other complementary diagnostic tests to increase the sensitivity and specificity.