Which feature helps ensure that the breath sample is not contaminated by mouth alcohol?

Which feature helps ensure that the breath sample is not contaminated by mouth alcohol?

• A. Visual color indicator
• B. Infrared energy absorption monitoring
• C. Humidity sensor
• D. Temperature compensation

Answer: (B)

Infrared energy absorption monitoring uses the specific spectral fingerprint of ethanol to quantify its concentration in the breath and verify the sample comes from the lungs (alveolar air) rather than from residual in the mouth. By examining how the breath absorbs infrared light at characteristic ethanol wavelengths and tracking the overall absorption pattern during the exhale, the instrument can detect inconsistencies that indicate mouth alcohol contamination. If the pattern doesn’t match a genuine alveolar sample, the test can be flagged or repeated, preventing a falsely elevated result from mouth alcohol. The other features don’t directly address this issue. A visual color indicator is just a display cue, not a detector of mouth alcohol. A humidity sensor isn’t a reliable indicator of mouth alcohol contamination, and temperature compensation adjusts readings for ambient heat, not the source of the ethanol signal.

Infrared energy absorption monitoring uses the specific spectral fingerprint of ethanol to quantify its concentration in the breath and verify the sample comes from the lungs (alveolar air) rather than from residual in the mouth. By examining how the breath absorbs infrared light at characteristic ethanol wavelengths and tracking the overall absorption pattern during the exhale, the instrument can detect inconsistencies that indicate mouth alcohol contamination. If the pattern doesn’t match a genuine alveolar sample, the test can be flagged or repeated, preventing a falsely elevated result from mouth alcohol.

The other features don’t directly address this issue. A visual color indicator is just a display cue, not a detector of mouth alcohol. A humidity sensor isn’t a reliable indicator of mouth alcohol contamination, and temperature compensation adjusts readings for ambient heat, not the source of the ethanol signal.