NONINVASIVE DETECTION OF HELICOBACTER-PYLORI INFECTION IN CLINICAL-PRACTICE - THE C-13 UREA BREATH TEST

Objectives: To validate the C-13 urea breath test for the detection of Helicobacter pylon infection both before and after treatment. Methods : C-13 urea breath tests with 125-mg and 250-mg doses were carried out on each of 60 infected and 60 noninfected subjects. Results were comp ared with histological examination of gastric biopsies to establish de tection limits. The best cut-off point was used in a clinical trial of the efficacy of the breath test in duodenal ulcer patients before and after antimicrobial therapy. The incremental increase (percentage, de lta over baseline in U of delta/mil) in respiratory (CO2)-C-13 abundan ce was associated with histological evidence of H. pylori. Outpatient, tertiary care medical center, acid secondary and primary care facilit ies were included. One hundred twenty healthy asymptomatic subjects an d 465 patients with duodenal ulcer disease were studied. The test kit assessed repeatability of breath sample collection and storage and sta bility of stored samples. Test performance was analyzed by comparison of 125-mg and 250-mg C-13 urea with measurements at 30 and 40 min post dose. The test was used to diagnose active H. pylori infection and gau ge success of antimicrobial therapy. Results: The test kit results wer e highly reproducible. The cut-off values were higher with 250-mg comp ared with 125-mg doses of C-13 urea and 40 min compared with 30 min. U sing a 125-mg C-13 urea and test detection limit of 2.4% at 30 min, th e accuracy was 94.8 (95% confidence interval = 92-97%) before antimicr obial therapy and 95.4% (95% confidence interval = 91-98%) after. An i ncrease of 2.4% in the abundance of breath (CO2)-C-13 measured 30 min after a 125-mg dose of C-13 urea reliably indicated the presence of ac tive H. pylori infection either before or after antimicrobial therapy. The C-13 urea breath test provides a simple and reliable and noninvas ive method of assessing H. pylori status.