Published in:
01-09-2009 | Original Article—Alimentary Tract
Use of the lactose-[13C]ureide breath test for diagnosis of small bowel bacterial overgrowth: comparison to the glucose hydrogen breath test
Published in: Journal of Gastroenterology | Issue 9/2009
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Purpose
The glucose hydrogen breath test (GHBT) is commonly used as a noninvasive test to diagnose small bowel bacterial overgrowth (SBBO) but its validity has been questioned. Our aim was to evaluate the lactose-[13C]ureide breath test (LUBT) to diagnose SBBO and to compare it with the GHBT, using cultures of intestinal aspirates as a gold standard.
Methods
In 22 patients with suspected SBBO (14 male, age range 18–73 years) aspirates were taken from the region of the ligament of Treitz under sterile conditions and cultured for bacterial growth. More than 106 colony-forming units/mL fluid or the presence of colonic flora was defined as culture positive (c+). After oral intake of 50 g glucose and 2 g of lactose-[13C]ureide, end-expiratory breath samples were obtained up to 120 min. The 13C/12C ratio in breath CO2 was determined by isotope ratio-mass spectrometry and hydrogen concentration in breath was analyzed electrochemically.
Results
After analyzing receiver operating characteristic curves of the LUBT results, total label recovery of >0.88% at 120 min was considered positive. The test had a sensitivity of 66.7% and a specificity of 100% to predict c+. In the GHBT, an increase of the signal of ≥12 ppm from baseline was considered positive. The sensitivity and specificity of the test were 41.7 and 44.4%, respectively.
Conclusions
The new stable isotope-labeled LUBT has excellent specificity but suboptimal sensitivity. In contrast, the standard GHBT lacks both high sensitivity and specificity. The LUBT is superior to the GHBT for detecting SBBO.