H 2-breath testing for carbohydrate malabsorption

Carbohydrate malabsorption is a frequent clinical condition often associated with abdominal disorders. Hydrogen-breath tests are considered practical and safe compared with more invasive methods in the diagnosis of these disorders. Our aim was to review the impact of carbohydrate breath tests in clinical practice and to propose a more standardized technique. Although particular emphasis has been placed on lactose breath test, fructose and sorbitol have also been considered. Original articles and reviews were searched in PubMed and the most relevant articles concerning clinical and methodological aspects of breath test were selected according to criteria of evidence based medicine. The search shows that breath testing can now be recommended in clinical practice to diagnose lactose malabsorption and intolerance in both adults and children. Criteria to perform this test and to record possible abdominal symptoms have been suggested. On the contrary, criteria of clinical utility for sorbitol and fructose breath tests are not yet acknowledged. In conclusion, lactose breath tests may be suggested in clinical practice following a standardized technique, while fructose and sorbitol tests should be proposed onlv for research studies.