Atypical breath test patterns provide unique insights into digestive health and treatment direction. Consequently, interpret results within the clinical context. In general, despite expert and research-based guidelines for diagnostic breath testing, the interpretation of results lacks a clear, universally accepted consensus. This leaves room for broad, sometimes varied clinical interpretation, making results more functional and insightful. As hydrogen and methane breath test markers signal different underlying conditions based on timing, peak patterns, and gas fluctuations, clinicians rely on experience and understanding of individual patient patterns.

Atypical Breath Testing Patterns

Breath tests are essential for diagnosing digestive issues such as small/large intestinal bacterial overgrowth (SIBO and LIBO). However, some results fall into atypical patterns, giving unique insights. Here’s an overview of six atypical breath test result patterns.

Flat Methane

In this case of atypical breath results, methane (CH₄) levels are elevated, but flat, throughout the small intestine (0–120 min) (Figure 1). Elevated methane gas levels throughout test results suggest increased bacterial activity throughout the intestines or elevated colonic activity combined with reduced gut motility.

Baseline Elevated Hydrogen

Initially high hydrogen (H₂) that either dips or remains high across the small intestine reflects potential pre-existing fermentation (Figures 2a, 2b). 

 

Flat Negative

Low hydrogen and methane (<3ppm) suggest low fermentative activity or microbial population (Figure 3).

Delayed Gut Motility

A hydrogen spike after 120 min with a second increase (double peak) shows slowed motility (Figure 4). Normally, a classic looking “double peak” of gas activity shows an initial spike in gas activity just prior to and after the intestinal transition zone (commonly around 100-120 min). The pattern becomes atypical when the double peak occurs outside of that time frame.

Multiple Peaks and Valleys

Fluctuating H₂/CH₄ peaks may result from uneven microbial distribution (Figure 5).  Causes include segmental delays in motility, uneven transit times with pockets of microbes at different points, and SIBO. Additionally, different bacterial species producing gas at varying rates can fluctuate gas levels. Finally, physiological gut responses with normal motility patterns or minor motility disorders may influence gas patterns in the intestines.

Atypical Colon

A notable hydrogen and/or methane spike in the colon indicates possible microbial imbalance in the large intestines (Figures 6a, 6b).

 

Conclusion

Each atypical breath test pattern reveals distinct physiological and microbial dynamics. By combining the results with the clinical presentation, healthcare providers can create highly targeted and personalized treatment plans for various GI concerns. In some cases, these trends can be difficult to interpret. Neurovanna offers healthcare providers using our breath tests free consults with our SIBO expert Dr. Bradley Bush. Become a Neurovanna healthcare provider for quality and exclusive test results as well as skilled clinical support.

This is part 3 of a three part series on common breath test trends. Read part 1 to learn about common trends for lactulose and glucose SIBO breath tests. Part 2 discusses common trends in fructose, sucrose, and lactose sugar malabsorption breath test results.