What the breath reading answers
A recent-combustion marker and a safety assessment answer different questions.
| Question | Interpretation |
|---|---|
| Recent combustion | Timing, protocol and cut-off govern what a sample can detect. |
| Nicotine use | CO cannot establish whether someone uses nicotine replacement or another non-combustible product. |
| CO safety | A smoking monitor does not clear a home or replace the response to a CO alarm. |
Why timing changes the answer
CO leaves the body after exposure stops. A test taken later can therefore miss smoking that occurred outside its detection window. The window also depends on the starting level, breathing and the cut-off chosen by the study; a low result is not a complete smoking history.
Combustion is the clue, not nicotine
Cigarettes produce CO when they burn. Nicotine replacement, smokeless products and many electronic devices do not produce the same CO pattern. A breath test cannot establish whether someone is using nicotine, and another combustion source can raise it.
Two devices may give different results
Breath-holding, calibration and the model used affect measurements. A study threshold is a rule for classifying that study’s samples, with missed cases and false positives; it is not a universal boundary between safe and dangerous exposure.
Use the testing service for interpretation
Ask which protocol, detection window and product definition the result belongs to. Keep readings in your own clinical record rather than entering them on this page. A smoking breath monitor does not replace assessment of suspected carbon monoxide exposure or the response to a household CO alarm.
Sources
The central claims on this page were checked against the sources below.
- SRNT / CDC repository: Biochemical verification of tobacco use and abstinence: 2019 update
Sources checked: 2026-10-11
- CDC: Carbon monoxide poisoning basics: household sources and alarms
Sources checked: 2026-10-11
General education; individual decisions belong with qualified local care.