Diagnostics - SIBO Testing Flashcards
What is SIBO?
SIBO stands for Small Intestinal Bacterial Overgrowth, which occurs when bacterial count in the small intestine exceeds 105 CFU/ml, leading to fermentation of carbohydrates and production of hydrogen or methane.
What substrates are used in SIBO testing?
Substrates used in SIBO testing include lactulose (popular but can give false positives), glucose (fewer false positives but may miss distal positives), and fructose (rarely used but helps detect fructose intolerance).
How is SIBO tested?
SIBO is tested using breath tests that measure gases (hydrogen, methane) produced by bacteria fermenting ingested substrates. Breath samples are collected every 20-30 minutes after the substrate is taken.
What is the role of lactulose in SIBO testing?
Lactulose is a popular substrate for SIBO testing but may give false positives because it can speed up intestinal transit time, leading to inaccurate results.
What is the role of glucose in SIBO testing?
Glucose is used in SIBO testing and has fewer false positives than lactulose but may not detect bacterial overgrowth in the distal small intestine because it is absorbed quickly.
What is the role of fructose in SIBO testing?
Fructose is rarely used in SIBO testing but can help identify fructose intolerance if there is a gas rise after 120 minutes.
What kind of diet is required before a breath test for SIBO?
A 24-hour strict diet is required before a SIBO breath test, avoiding microbiota-feeding foods. Allowed foods include meat/poultry/fish, steamed white rice, eggs, clear meat broth, fats/oils, and salt and pepper.
What hydrogen levels indicate a positive SIBO test?
A hydrogen rise of 20 ppm (parts per million) before 90 minutes indicates a positive result for SIBO.
What methane levels indicate a positive SIBO test?
A methane rise of 12 ppm (or as low as 3 ppm in cases of severe constipation) before 90 minutes indicates a positive result for SIBO.
What combined gas levels indicate a positive SIBO test?
A combined gas rise of 15 ppm before 90 minutes indicates a positive result for SIBO.
What does a gas rise after 120 minutes suggest in fructose testing?
A gas rise after 120 minutes during fructose testing suggests fructose intolerance.
Why are stool tests often combined with SIBO tests?
Stool tests are often combined with SIBO tests because SIBO rarely occurs alone and may be part of broader gut health issues.
