13C-Urea Breath Test for the Diagnosis ofHelicobacter pyloriInfection: A Further Simplification for Clinical Practice

Abstract

Background: The ¹³C-urea breath test is the most accurate noninvasive method for the diagnosis of Helicobacter pylori infection. The oral administration of citric acid solution as test drink 10 min before administration of ¹³C-urea appears to be the most valuable test procedure hitherto reported. To simplify the test for clinical routine, we evaluated in a prospective, randomized, crossover study the accuracy of a new modification that consists in giving the ¹³C-urea dissolved in the test drink. Methods: Forty dyspeptic patients were studied. H. pylori status was assessed by histology, rapid urease test, and culture. A ¹³C-urea breath test was performed on 2 consecutive days by giving 200 ml 0.1N citric acid solution either 10 min previous to (protocol 1) or simultaneously with (protocol 2) the administration of 75 mg ¹³C-urea in randomized order. The ¹³CO₂/¹²CO₂ ratio was measured in breath samples taken before and 10, 20, 30, 45, and 60 min after administration of ¹³C-urea. Results: Twenty patients were H. pylori-positive. In these subjects maximal delta values (28.1? (21.4-34.9) versus 30.6? (22.8-38.4)), expired cumulative amount of ¹³C (9.3% (6.9-11.7) versus 10.2% (7.4-12.9)), and time to maximal delta value (33 min (26-39) versus 35 min (29-42)) obtained by applying test protocols 1 and 2, respectively, were similar. Both test protocols provided negative results in all H. pylori-negative subjects. The ¹³C-urea was stable in citric acid solution at room temperature for at least 2 weeks. Conclusions: The ¹³C-urea breath test for the diagnosis of H. pylori infection can be simplified by giving the substrate dissolved in the test drink. This modification is not associated with a loss of diagnostic accuracy.