Metals, toxins and medication
Cotinine
Cotinine in urine shows whether someone has taken in nicotine in the past few days, from any source.
Everything about this testWhat it measures
The analysis measures how much cotinine is excreted in the urine. Cotinine is formed in the liver from nicotine and leaves the body through the kidneys. Cotinine is present in urine in higher concentrations than in blood, so even small amounts of nicotine become visible. The source can be smoking, but also an e-cigarette, snus or a nicotine replacement product.
- Nicotine intake in the past few days, from any source
- Low exposure, for example from secondhand smoke
High
A high value fits daily nicotine use. The level depends not only on how much nicotine has been taken in, but also on how much you have drunk: diluted urine gives a lower result. That is why the value is often corrected for creatinine. Nicotine patches, gum, e-cigarettes and snus give the same increase as cigarettes.
Low
A low or unmeasurable value fits someone who does not use nicotine. After quitting smoking, the value falls to unmeasurable over the course of a few days. Secondhand smoke gives a low but often still measurable value. Drinking a lot just before urinating can lower a result without less nicotine having been taken in.
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.
Reliability
Cotinine in urine is a sensitive measure of nicotine intake in the past few days and also shows secondhand smoke exposure. For an individual, the result adds little to what someone already knows about their own smoking. A single urine sample varies greatly with fluid intake; correction for the creatinine level is usual so that results can be compared. The result says something about nicotine intake in the past few days and nothing about the harm from smoking in that person.
Limitations
- Fluid intake strongly determines how concentrated the urine is; without correction for creatinine, results are hard to compare.
- Nicotine replacement products, e-cigarettes and snus give the same increase as cigarettes.
- The rate at which nicotine is broken down differs between people and changes during pregnancy, among other situations.
- 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. The percentage of smokers in the Netherlands is lower than the average in the European Union and is slowly falling.
Who is this useful for
The result is mainly meaningful when it is unclear whether someone uses nicotine. Sometimes the result matters for a medical question, for example around surgery or a treatment in which smoking strongly affects the outcome. For someone who wants to quit smoking, the measurement adds nothing to support.
Downsides and risks
- A measurable value due to secondhand smoke or a nicotine replacement product can wrongly be interpreted as smoking.
- A diluted urine sample can give a low result in someone who does smoke.
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