Combined orocecal scintigraphy and lactulose hydrogen breath testing demonstrate that breath testing detects orocecal transit, not small intestinal bacterial overgrowth in patients with irritable bowel syndrome.

摘要

In the last decade, there has been increased attention directed toward the pathologic role of luminal microflora, including the possible association of small intestinal bacterial overgrowth (SIBO) and intestinal dysfunction and symptoms in irritable bowel syndrome (IBS). SIBO is historically defined as >10s colony forming units (CFU)/mL (Am J Gastroenterol 1996;91:1795-1803). Recently, there has been a resurgence in the use of the lactulose hydrogen (H_2) breath test (LHBT) as a presumptive surrogate marker for SIBO in IBS. However, some studies have suggested that up to 85% of healthy individuals have an abnormal LHBT (Am J Gastroenterol 2008; 103:958-963), calling into question the validity of using this test to discriminate IBS from healthy subjects.