Digestive Diseases and Nutrition

Breath Tests

Breath testing is used as an ancillary diagnostic tool for certain medical conditions presenting with symptoms such as diarrhea, bloating and abdominal distension, and abdominal pain, alone or as part of irritable bowel syndrome (IBS). These symptoms can be the result of small intestinal bacterial overgrowth (SIBO), food intolerances such as lactose or fructose intolerance, and certain infections such as H. pylori. SIBO is not an acquired infection (from eating or drinking). The small numbers of bacteria that normally reside in the small intestine grow, for a number of reasons, beyond the normal limits. The result is an increase in bacterial fermentation of some of the ingested food that creates gases and other compounds causing the symptoms associated with SIBO (mainly diarrhea, bloating, and abdominal pain). These gasses include hydrogen (H2), carbon dioxide (CO2), and methane (CH3) that can be measured in breath samples after the test substance is administered to the patient. SIBO is a treatable condition with remarkable improvement seen in as little as few days after initiating the appropriate antibiotic(s). SIBO is also one of the causes of vitamin B12 deficiency and it is important to check for this condition in a patient with this deficiency.

For each medical condition, a different test substance is given to a patient to swallow. For example, lactulose (an indigestible synthetic sugar) is used as test substance for SIBO, the sugar lactose for lactose intolerance, and urea in a capsule form for H. pylori. Breath tests are simple, non-invasive, and are performed after a short period of fasting (typically 8–12 hours). Certain dietary restrictions are necessary prior to the test and will be provided to you as the test when the test scheduled. It is also important not to take antibiotics for 14 days prior to the test.

 QuinTron BreathTracker™ SC Digital MicroLyzerAt the Division of Digestive Diseases and Nutrition at USF Morsani College of Medicine, we offer the lactulose breath test for SIBO. We utilize the latest gas chromatograph equipment, the QuinTron BreathTracker™ SC Digital MicroLyzer. The test is administered in the clinic area on the 6th floor and it will take up to 3 hours starting at 8:00 o’clock in the morning. While a driver is not needed, we suggest that you bring some reading material or good music to keep yourself entertained.

A baseline breath sample is collected, and then additional samples are collected at 20 minute intervals for up to 3 hours. Once positive results are reached, the test is terminated. A rise in breath hydrogen or methane of 20 parts-per-million (ppm) or greater over baseline within the first two hours indicates bacteria in the small intestine. A delayed response may be caused by colonic bacterial fermentation. The results will be conveyed to you within 3-5 business days and treatment will be initiated, if appropriate, accordingly.