STUDIES OF C-13-UREA BREATH TEST FOR DIAGNOSIS OF HELICOBACTER-PYLORIINFECTION IN JAPAN

In recent years Helicobacter pylori infection has been implicated in t he etiology of a variety of upper gastrointestinal diseases. The aim o f this multi-center trial was to search for tile cut-off value of the simple C-13-urea breath test (C-13-UBT) for diagnosis of N. pylori inf ection, and to examine the sensitivity and specificity of C-13-UBT for culture, the rapid urease test (CLO lest) histology, and serological tests. Two hundred and forty-eight patients participated in this study after giving their informed consent. Endoscopic biopsy specimens were taken from gastric antrum and corpus for culture (190 patients), CLO test (222 patients), and histology (98 patients). A serological test w as carried out for all patients. H. pylori infection was established w hen culture was positive or more than two of the tests, histology, CLO test, and serological test, were positive, and noninfection status wa s established when the all tests more than two tests were negative. Af ter baseline breath samples were taken, the patients (who had fasted) were given 100mg of C-13-urea in 100ml water while sitting: they washe d out the mouth with water. They were then placed in the left lateral decubitus position for 5 min, and additional breath samples were taken 10, 20, 30, 45, and 60 min after urea administration, with patients i n the sitting position. One hundred and sixty-five of the 248 patients were infected, 45 were not infected, and H. pylori infection status w as not evaluated in 35 by endoscopic and serological tests. Breath sam ples at 20 min were employed to determine the cut-off value. Using the receiver operating characteristic (ROC) curve, we determined the cut- off value for a positive UBT at 2.5 Delta parts per thousand. The sens itivities of UBT for culture, CLO test, histology, and serological tes t were 98.4%, 98.6%, 100.0%, and 92.5%, and the specificities were 78. 8%, 82.5%, 83.3%, and 87.3%, respectively. The cutoff value of C-13-UB T for the diagnosis of H. pylori infection was 2.5 Delta parts per tho usand; this test is a simple and noninvasive method for the diagnosis of this infection and has high sensitivity and specificity.