Carbon Monoxide (CO) Breath Test Monitoring

Numed Healthcare supplies a range of market leading Carbon Monoxide (CO) breath test monitors and accessories from MD Diagnostics. 

CO breath test monitoring is a valuable motivational tool for smokers to encourage them to stop smoking and research shows that smokers are more likely to make a successful quit attempt if a CO monitor is used as part of their plan.

One of our most popular CO breath monitors is the CO Check Pro Carbon Monoxide Breath Monitor. It offers coloured light indicators to signify smoking level and the results are displayed instantly on the large screen.


What is a CO breath test?

A CO breath test shows how much carbon monoxide – a poisonous gas is in a person’s body. Carbon monoxide from smoking reduces the ability of red blood cells to carry oxygen. A single breath will instantly display results in CO part per million (PPM) or % Carboxyhemoglobin (%COHb) – the amount of carbon monoxide attached to a person’s red blood cells represented as a percentage.

How does smoking elevate COHb?

In a typical puff of a cigarette smoke there is about 5% CO by volume. Carbon monoxide actively competes with oxygen to bind to the red blood cells in the blood stream. (carbon monoxide has approximately 250 times greater affinity to haemoglobin in red blood cells than oxygen) when carbon monoxide binds with the red blood cells it forms carboxyhaemoglobin (COHb)). This will eventually be excreted via the lungs; the same way it went into the body.

How quickly does the CO disappear from the body after smoking stops?

It takes approximately 5 to 6 hours to reduce the original level of carbon monoxide by half. Usually after a maximum period of 48 hours the ex-smoker would show the level of a non-smoker living in the same environment.

How long after a cigarette should the test by conducted?

Ideally more than 10 minutes should elapse between exhaling into the monitor and when the last cigarette was smoked.

How hygienic is a CO breath test using an MD Diagnostic CO breath monitor?

MD Diagnostics recommend the use of SafeBreath filtered cardboard mouthpieces. SafeBreath mouthpieces have an in-built bacterial and viral filter ensuring >99% efficacy. This results in complete hygienic solution and avoids cross contamination between individuals being tested and protects both patients and equipment. SafeBreath mouthpieces are single patient use and should be disposed of after the individual has been tested on the CO breath monitor.

What else does breath CO show?

It acts as an indicator as to the possible level of some 4000 toxic substances in cigarette smoke, some 60 of which cause cancer.

Are the CO monitors CE Marked?


Are the CO monitors IEC 60601 Electrical Safety Standard Compliant?


Is the useful life of each CO monitor 2 year or 5 years?

The device has a 5 year warranty except for the electrochemical fuel cell which has an expected life of two years and is therefore excluded from the warranty.  The electrochemical fuel cell works in a similar way to a battery and therefore the more you use it the shorter it’s life. The chemical is used up as it combines with the CO in the exhaled breath, which produces a current that is proportional to the CO concentration.  In normal use the cell will last at least 2 years but if it is used regularly with high levels of CO, or exposed to abnormally high levels of CO, it may need to be replaced sooner.