Modification of baseline status to improve breath tests performance

Area of Science:

• Gastroenterology
• Clinical Diagnostics
• Respiratory Physiology

Background:

• Breath tests for carbohydrate malabsorption rely on low baseline hydrogen (H₂) and methane (CH₄) levels.
• High baseline levels (H₂ ≥ 20 ppm, CH₄ ≥ 10 ppm) often lead to test cancellation, despite adherence to preparation protocols.

Purpose of the Study:

• To investigate if light physical activity, specifically walking, can reduce elevated baseline H₂ and CH₄ levels in patients undergoing breath testing.
• To assess the impact of reduced baseline levels on test outcomes and diagnostic accuracy.

Main Methods:

• Retrospective analysis of baseline H₂ and CH₄ levels from 1552 breath tests.
• Comparison of initial baseline (B1) levels with levels obtained after a one-hour light walking session (B2) in patients with elevated B1.

Main Results:

• Light walking for one hour decreased H₂ by 8 ppm and CH₄ by 2 ppm in patients with elevated baseline levels.
• 40% of tests with elevated B1 had B2 levels below the recommended cut-offs.
• 10% of tests initially negative based on B1 became positive using B2, while all initially positive tests remained positive.

Conclusions:

• Re-sampling after light walking is a viable strategy to enable breath testing in patients with previously elevated baseline gas levels.
• Utilizing the second sample (B2) for calculations can identify malabsorption cases that might otherwise be missed, improving diagnostic yield.