Non-Invasive Detection of Low-Intestinal Lactase Activity in Children by Use of a Combined ¹³CO₂/H₂ Breath Test

Abstract

Background: The aim of the study was to diagnose hypolactasia with a higher accuracy than with the traditional H₂ breath test. Methods: We used a combined ¹³C-lactose ¹³CO₂/H₂ breath test, which was performed in 33 patients in whom lactase activity was measured. Results: Lactase activity was reduced in 13 cases. The sensitivity and specificity of the H₂ test were 54% and 90%; those of the ¹³CO₂ test 69% and 70%. False-negative results did not always occur in the same patients. In five of six patients with both test results abnormal, lactase activity was low. In 13 of 15 patients with both test results normal, lactase activity was normal. In 6 of 12 cases with only 1 test abnormal, lactase activity was low. Conclusion: The combined H₂/¹³CO₂ breath test (sensitivity, 85%; specificity, 65%) is more adequate for diagnosis of hypolactasia than the H₂ breath test alone.