Endoscopic-Assisted Glucose Breath Test (EAGBT) for Evaluating Distal Small Intestinal Bacterial Overgrowth (SIBO):...

Diagnosis of Small Intestinal Bacterial Overgrowth (SIBO) remains challenging. Traditional glucose breath testing (GBT) is useful but has low sensitivity, because glucose is absorbed proximally and misses distal SIBO. There is no definitive test for distal SIBO. To develop and investigate the usefulness of endoscopically-assisted glucose breath test (EAGBT) in patients with SIBO.

Patients with unexplained gas/bloating and distension and a negative GBT completed gas/bloating questionnaire, underwent upper endoscopy with duodenal aspirates/cultures and placement of aspiration catheter to ligament of Treitz. Post-endoscopy, 37.5 g of glucose dissolved in 100 mL water and 0.65 microcuries of Tc99m was infused into the jejunum with simultaneous nuclear imaging and breath hydrogen (H₂) and methane (CH₄) assessments. A rise in breath H₂/CH₄ with radioisotope within the small bowel was defined as true positive EAGBT test. Correlational analyses were performed by a blinded investigator.

Of twelve patients, five (42%) had positive EAGBT, four (33%) had negative test, and three (25%) had false positive test. The most common symptoms at baseline and during testing were bloating and flatulence (> 80%). The overall concordance between imaging and breath testing was 75% with moderate agreement (κ = 0.53,95% CI: 0.12-0.94; p-value = 0.038). Duodenal cultures were negative.

EAGBT may be a useful method of assessing distal SIBO with good agreement between imaging and breath testing. In patients with unexplained gas/bloating and negative GBT/culture, although invasive, EAGBT could facilitate diagnosis of SIBO.