13C-urea breath test for the diagnosis of Helicobacter pylori infection. A further simplification for clinical practice.

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 per thousand (21.4-34.9) versus 30.6 per thousand (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.