Stable isotope techniques for the detection of Helicobacter pylori infection in clinical practice. 13C-urea breath test in different experimental conditions

RESUMO

The (13)C-UBT has been demonstrated to be a reliable method for the evaluation of Helicobacter pylori infection. The aim of our work is to determine the cut-off point of the (13)C-UBT for samples collected as gas or collected in a solution of triethanolamine. For this purpose, patients fasted for at least 6 hours were able to collect basal samples before the administration of 65 mg of (13)C-urea solution. Breath samples were taken 10,30 and 60 minutes after the administration of the labeled solution. All the samples were collected in gas collectors and in glass vials containing 1 ml of a 7 per cent triethanolamine solution. The cut-off points for gas collected samples were established in 4.0 per cent and for 10, 30 and 60 minutes samples, respectively, while for the samples, collected in triethanolamine solution, cut-off points were established in 5.0 per cent, for the 10 minutes samples, in 3.5 per cent for the 30 minutes samples and 4.7 per cent for the 60 minutes samples. We found that this test has a sensitivity of 100 per cent and a specificity of 100 per cent for H. pylori detection in both experimental conditions, when multiple breath samples are taken. If we considered only the 30 minutes time, sensitivity and specificity diminish for the gas collected samples. We conclude that the collection of breath samples in triethanolamine solution allows a better differentiation between H. pylori infected and non infected patients than gas collected samples.