As functional GI disorders, such as Small Intestinal Bacterial Overgrowth (SIBO), Intestinal Methanogen Overgrowth (IMO), and carbohydrate malabsorption, continue to challenge clinicians due to symptom overlap and diagnostic ambiguity, new research underscores an important truth: symptoms and history alone are not reliable predictors of breath test outcomes.
A large-scale 2024 study conducted by our research partners at The Functional Gut Clinic in the UK and recently published in 2025 by the American Journal of Gastroenterology (AJG) reinforces the essential role of objective hydrogen and methane breath testing (HMBT) in diagnostic accuracy.
Study Overview:
In this retrospective review of over 5,000 adult patients who underwent hydrogen and methane breath testing for suspected SIBO/IMO or carbohydrate malabsorption, researchers evaluated whether patient-reported symptoms and medical history could predict test results. The findings were clear:
- No single symptom—or even combinations of symptoms—reliably predicted a positive or negative breath test outcome.
- Although certain demographic trends (e.g., higher methane positivity among older patients and women) were observed, they were not strong enough to guide diagnosis without testing.
- Common GI symptoms like bloating, constipation, diarrhea, and abdominal pain were found across both positive and negative test populations, limiting their diagnostic utility.
Key Takeaways:
- Clinical symptoms alone are insufficient to determine the presence of SIBO/IMO or carbohydrate malabsorption.
- Objective testing remains essential to guide accurate diagnosis and individualized treatment.
- Over-reliance on patient history can result in misdiagnosis, delayed care, or ineffective treatments.
The CDI Advantage in At-Home Breath Testing:
CDI’s clinically validated, non-invasive at-home breath tests offer fast, accurate, and accessible diagnostics for:
- SIBO and IMO for Adult GI
- SIBO and IMO for Pediatric GI
- Lactose, Fructose, and Sucrose Malabsorption for Adult and Peditaric GI
Paired with robust clinical support, industry-leading lab turnaround times, MyGI Gateway portal access, and the highest standards of diagnostic integrity, CDI empowers providers to move from guesswork to precision.
Want to ensure your practice is maximizing the value of every breath test ordered?
Visit CDI’s Provider Resource Center or contact CDI’s Provider Services team for personalized support.
