Nicotine/cotinine

What is being tested?
Nicotine is an addictive alkaline chemical found in the tobacco plant and concentrated in its leaves. It is inhaled with every puff of a cigarette and swallowed when chewing tobacco. Nicotine is metabolised by the liver into more than 20 compounds, which are excreted by the kidneys in the urine. Both tobacco use and exposure to tobacco smoke can raise the concentrations of nicotine and its main metabolite, cotinine, in the body. Levels also rise with nicotine replacement products, such as nicotine patches and chewing gum. In large amounts, nicotine can be poisonous.

Cotinine is the main metabolite of nicotine and is usually the preferred test for assessing tobacco use or smoke exposure, because it is stable and is produced only when nicotine is metabolised. Cotinine has a half-life in the body of 7 to 40 hours, while nicotine has a half-life of 1 to 4 hours. Blood and/or urine cotinine tests may be requested together with nicotine tests. In some cases other nicotine metabolites, such as nicotine-1′-N-oxide, trans-3′-hydroxycotinine or nornicotine, or other tobacco chemicals, such as anabasine in urine, may also be tested.

The presence of nicotine and/or cotinine in a person’s sample may indicate the use of tobacco products or exposure to environmental tobacco smoke. The tests can be used in a number of situations to assess possible use of tobacco products, for example in stop-smoking programmes, pre-employment checks and assessments of applicants for health or life insurance.

Nicotine and cotinine tests may also be requested when nicotine poisoning is suspected. An acute nicotine overdose, as could happen if a child swallowed nicotine lozenges or chewing gum, usually needs immediate medical attention. Symptoms can include burning in the mouth, nausea, abdominal pain, excessive salivation (hypersalivation), diarrhoea, sweating, confusion, dizziness, agitation, an increased heart rate, rapid or difficult breathing, seizures, coma and even death.

How is the sample collected for testing?
A blood sample is taken by inserting a needle into a vein in the arm and/or a random urine sample is collected. Occasionally a saliva sample may be obtained, either directly or by soaking a pad or swab with saliva. Rarely, a hair sample is collected.

Is any preparation needed to ensure the quality of the sample?
No preparation is needed for the test.

How is it used?
When is it requested?
What does the test result mean?
Is there anything else I should know?

How is it used?
Nicotine or its primary metabolite, cotinine, is often tested to assess tobacco use. Long-term use of tobacco products can increase the risk of developing many diseases, including lung cancer, COPD, stroke, heart disease and respiratory infections, or make asthma worse and promote blood clots. In pregnant women, smoking can slow the baby’s growth and cause low birth weight.

Since tobacco use can greatly affect a person’s health, companies may use nicotine/cotinine tests to assess prospective employees for tobacco use. Many health and life insurance companies also test applicants for nicotine/cotinine.

Both nicotine and cotinine can be measured qualitatively or quantitatively. Quantitative tests can help distinguish between active smokers, smokers who have recently stopped, non-smokers who have been exposed to significant environmental smoke and non-smokers who have not been exposed.

Cotinine can also be measured in saliva or hair, although hair testing is mainly used in research, for example in studies of non-smokers’ exposure to tobacco smoke.

Blood and urine nicotine may be requested on its own or together with cotinine if the doctor suspects that someone has taken a nicotine overdose.

When a patient says they are using nicotine replacement products but no longer smoke, urine nicotine, cotinine and anabasine may sometimes be requested. Anabasine is present in tobacco but not in commercial nicotine replacement products. If a sample is positive for anabasine, the person is still using tobacco products.

When is it requested?
Cotinine and/or nicotine tests may be requested whenever tobacco use or exposure to tobacco smoke needs to be assessed. When a person joins a stop-smoking programme, blood and urine cotinine tests may be requested to check that the rules are being followed. Urine, blood or saliva tests may be carried out to screen for tobacco use when someone applies for health or life insurance, or applies for a job with an employer that bans smoking. The tests may also be ordered by a court in child custody cases. Since smoking increases the risk of medical complications, the tests may be carried out before starting certain drug treatments or before surgery.

Nicotine and cotinine are sometimes measured when a patient has symptoms that the doctor suspects may be due to a nicotine overdose. Symptoms of mild nicotine poisoning can include:

• nausea, vomiting
• dizziness
• excessive salivation
• weakness

More severe nicotine poisoning can result in:

• increased blood pressure and/or heart rate, which then suddenly fall
• slowed or difficult breathing
• seizures
• coma

Hair tests are rarely carried out in clinical settings, but may be requested when an assessment of longer-term tobacco use is wanted.

What does the test result mean?
In the blood, nicotine levels can rise within seconds of a puff on a cigarette. The amount depends on the nicotine content of the cigarette and on how it is smoked, for example how deeply the smoke is inhaled. Test results are not interchangeable. Concentrations will be higher in urine than in blood or saliva. There is also some variability from person to person and some genetic differences in the rate at which nicotine is metabolised and cotinine is eliminated from the body. When someone stops using tobacco and nicotine products, it can take more than two weeks for blood cotinine levels to fall to those of a non-tobacco user, and several weeks for urine levels to fall to very low concentrations.

In general, high levels of nicotine or cotinine indicate active use of tobacco or nicotine replacement products. Moderate concentrations indicate a tobacco user who has not taken tobacco or nicotine for two or three weeks. Lower levels may be found in a non-tobacco user who has been exposed to environmental smoke. Very low or undetectable concentrations are found in non-tobacco users who have not been exposed to environmental smoke, or in tobacco users who have not used tobacco or nicotine for several weeks.

Patients with an obvious nicotine overdose are not usually tested for nicotine or cotinine. Concentrations would typically be raised, but levels do not necessarily correspond to the severity of the patient’s symptoms.

Is there anything else I should know?
Some pesticides contain high concentrations of nicotine. This can be another source of nicotine poisoning.

A person’s genetic make-up can influence how they metabolise nicotine. Variations in the genes that produce the liver enzyme CYP2A6 affect the rate of nicotine metabolism.

1. Are there forms of tobacco that do not contain nicotine?
2. Can I be required to be tested for tobacco use?
3. Where can I find information on how to stop smoking?
4. What types of nicotine replacement products are available?

1. Are there forms of tobacco that do not contain nicotine?
No, they all contain nicotine. This includes pipe tobacco, cigars, snuff, chewing tobacco, etc. If you use any of these forms, nicotine may be detected in your body.

2. Can I be required to be tested for tobacco use?
Since tobacco use is legal for adults, this could only be done for people tested on the order of a court, for example in child custody cases. However, since smokers tend to have higher health costs and are at greater risk of developing a range of diseases, some health and life insurance companies may require applicants to be tested for tobacco use before accepting them as customers.

3. Where can I find information on how to stop smoking?
Many national organisations and government resources are available. See the contacts for further information.

4. What types of nicotine replacement products are available?
There are many over-the-counter (OTC) products and some available on prescription. OTC products include nicotine chewing gum, patches and lozenges. Those available on prescription include nicotine patches, inhalers and nasal sprays. It is important to follow the instructions for use and to keep them away from children. These products are intended to be used together with stop-smoking programmes. Talk to your doctor to find out the best options for you.