Quality control study of H-2 breath testing for the diagnosis of carbohydrate malabsorption in Italy

Background and Aims. H-2 breath testing is increasingly used in Italy. The aim of this multicenter study was to assess the accuracy of this technique in the diagnosis of carbohydrate malabsorption. Methods. An anonymous questionnaire was used to collect information about H-2 breath testing methods and to design the quality control study. Fifteen out of 23 laboratories responded to the questionnaire and 12/23 completed the entire study. Results, The survey revealed that a large variety of H-2 testing methods are employed in Italy, but none have been previously tested for accuracy. This prospective study showed that these tests fail to identify > 20% of patients with malabsorption. In contrast, a new method based on single H-2 breath measurement at 6 hours after lactulose ingestion and a cutoff value of greater than 5 ppm, had a sensitivity of 92% +/- 4% and a specificity of 94% +/- 0.5%. Increasing the cut-off to 10 ppm resulted in a sensitivity of 88% +/- 9% and a specificity of 100%. This improved accuracy was obtained with a much simpler testing procedure in which only one breath sample is analyzed in contrast to the baseline and multiple subsequent samples that are analyzed using the currently employed techniques. Conclusions. A great improvement in the accuracy of the H-2 breath test, as well as a considerable saving in terms of time and costs, may be possible through the use of a new, simplified H-2 breath test followed by careful H-2 analysis.