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Interactive Tool

Breath Test Interpreter

Type in the hydrogen, methane and (if measured) hydrogen sulfide values from your lab report to see how they compare with the published diagnostic thresholds.

This is not a diagnosis. The tool applies published criteria to the numbers you enter so you can understand your report and prepare questions. Everything runs in your browser and nothing you type is sent or stored. Only a clinician who knows your history can diagnose and treat you.

Your readings

Values in parts per million (ppm). Leave a cell empty if your report has no reading for that time.

Breath test readings in ppm by minute
Minute H₂ CH₄
0 (baseline)
15
30
45
60
75
90
105
120
135
150
165
180

The thicker line marks the end of the 90-minute window used for hydrogen.

What the thresholds say

Your graph

How this interpreter reads your results

  • Hydrogen: positive when it rises at least 20 ppm above the 0-minute baseline within the first 90 minutes (North American Consensus). An early rise of 10 to 12 ppm is shown as borderline because European guidelines count it as positive.
  • Methane: positive for intestinal methanogen overgrowth when any reading is 10 ppm or higher.
  • Hydrogen sulfide: positive when any reading is 3 ppm or higher, the cut-off used by the Trio-Smart test. There is no consensus threshold yet.

Labs and clinicians may use different criteria, and transit speed, preparation mistakes and the choice of sugar all affect results. Read our full guide to SIBO breath tests for the details, and take your report to the clinician who ordered it.