Metals, toxins and medication
Cotinine
Cotinine is the breakdown product of nicotine and shows whether someone has taken in nicotine in the past few days.
Everything about this testWhat it measures
The analysis measures how much cotinine is in your blood. Cotinine is formed in the liver from nicotine and stays in the body much longer than nicotine itself. This makes cotinine a better measure of recent nicotine use than nicotine. The source can be a cigarette, but also an e-cigarette, snus, nicotine gum or a nicotine patch.
- Nicotine intake in the past few days, from any source
- Distinguishing between someone who does and does not smoke, when there is a specific question
High
A high value fits daily nicotine use. The higher the value, the more nicotine has been taken in over the past few days, but the link is not exact: people break down nicotine at different rates. Nicotine replacement products such as patches, gum and lozenges also give high values, as do e-cigarettes and snus. A high value says nothing about the harm from smoking in that person.
Low
A low or unmeasurable value fits someone who does not use nicotine. After stopping, the value falls to unmeasurable within a few days. Secondhand smoke can give a low but still measurable value. A low value in someone who does smoke can mean that they smoked little or not at all shortly before the blood draw.
If your result is abnormal
There is no standard medical follow-up to an abnormal result. If you want to quit smoking, the GP or practice nurse offers support, with or without medicines.
Reliability
Cotinine is a reliable measure of nicotine intake in the past few days and can also show secondhand smoke exposure. For an individual, the result adds little to what someone already knows about their own smoking. The result says something about nicotine intake in the past few days and nothing about the effects of smoking on the lungs, heart or blood vessels.
Limitations
- Nicotine replacement products, e-cigarettes and snus give the same increase as cigarettes; the result does not say where the nicotine comes from.
- The rate at which nicotine is broken down differs greatly between people and is different during pregnancy, among other situations.
- With secondhand smoke, the value is low but measurable, so someone can wrongly be seen as a smoker.
- There are no agreed cut-off values; the laboratory decides which cut-off it uses.
How common is this
About 17.8 percent of Dutch adults smoke. In all age groups, more men than women smoke, and smoking is more common among people with a lower income.
Who is this useful for
The result is mainly meaningful when it is unclear whether someone uses nicotine; if you want to quit smoking, support is more helpful than a measurement. Sometimes the result matters for a medical question, for example before surgery or a treatment in which smoking strongly affects the outcome. In people without such a question, the measurement adds nothing.
Downsides and risks
- A measurable value due to secondhand smoke or a nicotine patch can wrongly be interpreted as smoking.
- The result can start to work as a means of control rather than as help with quitting, which tends to make the conversation about smoking harder rather than easier.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results