What does the Breath Hydrogen Sulfide (H2S) test measure?

Why is Breath Hydrogen Sulfide (H2S) measured?

Hydrogen sulfide measurement is the genuine novelty of this panel and addresses a real diagnostic gap, since patients with hydrogen sulfide–predominant overgrowth were previously undetected on conventional testing and were left without a biochemical explanation for their symptoms. It is also the least validated component: diagnostic thresholds are proprietary rather than consensus-derived, published outcome data linking hydrogen sulfide results to treatment response remain limited, and the clinical significance of intermediate values is not established. It should be interpreted as an emerging measure that adds information rather than as a validated diagnostic threshold.

Reference ranges

Standard reference

Reported against the manufacturer's proprietary threshold; hydrogen sulfide criteria are not established in consensus guidelines and differ from those for hydrogen and methane

Functional medicine optimal

Not applicable — breath testing is a diagnostic assessment, not a marker with a functional optimal value

Units

ppm

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.