THE C-13-UREA BREATH TEST AS A PREDICTOR OF INTRAGASTRIC BACTERIAL LOAD AND SEVERITY OF HELICOBACTER-PYLORI GASTRITIS

Background: The urea breath test (UBT) has been proposed as the most a ccurate test for diagnosing Helicobacter pylori infection. The aim of this work was to evaluate the accuracy of the UBT and to compare the r esults with histologic and endoscopic findings in H. pylori infected p atients. Methods: One-hundred-and-seventy-two consecutive dyspeptic ou tpatients were studied by means of endoscopy (with histology and cultu re), UBT (75 mg C-13-urea), and serology. Gastritis was classified in accordance with the Sydney criteria. In H. pylori positive patients, t he bacterial load was assessed semiquantitatively, the number of bacte ria in histologic specimens being counted. UBT results were expressed either as percentage cumulative dose of (CO2)-C-13 excreted at 1 h (CD 60) or delta over baseline at 30' (DOB30). Results: Of 172 patients, 1 26 (73%) were H. pylori positive on histology or culture. Using a cut- off value of 3.3 parts per thousand for DOB30, the sensitivity, specif icity and accuracy of the UBT were 96%, 93.5%, and 95.3%, respectively . A significant correlation was observed between DOB30 values and intr agastric bacterial load (r=0.32). Moreover, a significant difference i n DOB30 values was found between patients sorted by the depth of infla mmation (chi(2)=4.36, p=0.036). No correlation was observed between DO B30 and endoscopic findings in H. pylori positive subjects. Conclusion s: The UBT is an accurate non-invasive diagnostic tool and can be used to predict both the intragastric bacterial load and the severity of r elated gastritis.