A recent study concludes that a single methane measurement (SMM) from a hydrogen and methane breath test can accurately diagnose intestinal methanogen overgrowth (IMO), potentially replacing the standard 2-hour breath test. A Single Fasting Exhaled Methane Level Correlates With Fecal Methanogen Load, Clinical Symptoms and Accurately Detects Intestinal Methanogen Overgrowth, which analyzes the ability of SMM to diagnose IMO, was published in the January 2022 issue of The American Journal of Gastroenterology.
An Alternative to the 2-Hour Breath Test
The current gold standard for diagnosing IMO is a 2-hour breath test, typically performed at a physician’s office as a point-of-care diagnostic test. The time-consuming nature can become excessive and difficult for both the patient and office staff, especially for those patients who require frequent monitoring for treatment response.
A new method of diagnosing IMO involves a fasting single methane measurement (SMM), but previous evidence concerning its effectiveness in diagnosing IMO is limited.
SMM shows promise for diagnosing IMO because patients with IMO exhibit elevated fasting methane levels but less incremental changes in breath methane after sugar ingestion. After ingesting sugar, this lack of increase suggests that the 2-hour breath test may not be necessary to receive an accurate diagnosis.
Determining SMM Accuracy
The study utilized two large independent breath test databases to determine the diagnostic accuracy and optimal cutoff of a fasting single methane measurement (SMM) to diagnose IMO.
A breath sample was collected in a single-patient breath collection upon arrival to the laboratory. For the 2-hour breath tests, participating subjects were asked to consume a low-fermentable diet starting 24 hours before the breath test and fast for the last 12 hours. Subjects then consumed 10g of lactulose or 75g of glucose, and from this point, breath samples were collected every 15 minutes for 2 hours.
Of the 12,183 lactose breath tests from unique subjects (excluding 2,664 repeat breath tests), 1,891 were diagnosed with IMO based on the 2-hour breath test.
For SMM, various cutoffs were assessed (3-10 ppm), and sensitivity and specificity analysis produced results that supported SMM’s ability to diagnose IMO. SMM was also proven to diagnose IMO accurately using the 2-hour glucose breath test, analyzing a database of 733 subjects, 147 with IMO subjects.
In addition, the study found that SMM performed on a particular day as the 2-hour lactulose breath test, precisely two weeks later, was also able to diagnose IMO accurately. Comparisons were made on subjects on days 1 and 14, with no treatment administered to the patients between these two screening days. This analysis found that individuals with IMO who do not receive active treatment maintain stable SMM over time, with no significant decreases.
Breath Testing for IMO
The results of this study suggest that single fasting exhaled methane measurement from both the lactulose and glucose breath test can accurately diagnose IMO using the same cutoff recommended by the North American Consensus (SSM ≥10 ppm). The study also concluded that SMM ≥10 ppm is associated with constipation and correlates with stool M. smithii. SMM measurements remained stable for 14 weeks without treatment, and antibiotic treatment decreased SMM after two days.
The validation of hydrogen and methane breath tests for diagnosis of IMO and monitoring treatment response is significant for the GI industry, which until recently didn’t even differentiate IMO from SIBO. Hydrogen and methane breath tests provide greater convenience for initial diagnosis and treatment monitoring as they are less time-consuming and can be completed from the comfort of a patient’s home.
Per the study discussion, “Although further validation studies are needed, SMM shows promise as an inexpensive, noninvasive biomarker for intestinal methanogen load.”
