C-13-UREA BREATH TEST FOR THE DIAGNOSIS OF HELICOBACTER-PYLORI INFECTION - A FURTHER SIMPLIFICATION FOR CLINICAL-PRACTICE

Background: The C-13-urea breath test is the most accurate noninvasive method for the diagnosis of Helicobacter pylori infection. The oral a dministration of citric acid solution as test drink 10 min before admi nistration of C-13-urea appears to be the most valuable test procedure hitherto reported. To simplify the test for clinical routine, we eval uated in a prospective, randomized. crossover study the accuracy of a new modification that consists in giving the C-13-urea dissolved in th e test drink. Methods: Forty dyspeptic patients were studied. H. pylor i status was assessed by histology, rapid urease test, and culture. A C-urea breath test was performed on 2 consecutive days by giving 200 m l 0.1 N citric acid solution either 10 min previous to (protocol 1) or simultaneously with (protocol 2) the administration of 75 mg C-13-ure a in randomized order. The (CO2)-C-13/(CO2)-C-12 ratio was measured in breath samples taken before and 10, 20, 30, 45, and 60 min after admi nistration of C-13-urea. Results: Twenty patients were H. pylori-posit ive. In these subjects maximal delta values (28.1 parts per thousand ( 21.4-34.9) versus 30.6 parts per thousand (22.8-38.4)), expired cumula tive amount of C-13 (9.3% (6.9-117) versus 10.2% (7.4-12.9)), and time to maximal delta value (33 min (26-39) versus 35 min (29-42)) obtaine d by applying test protocols 1 and 2, respectively, were similar. Both test protocols provided negative results in all H. pylori-negative su bjects. The C-13-urea was stable in citric acid solution at room tempe rature for at least 2 weeks. Conclusions: The C-13-urea breath test fo r the diagnosis of H. pylori infection can be simplified by giving the substrate dissolved in the rest drink. This modification is not assoc iated with a loss of diagnostic accuracy.