To detect the presence of and/or measure the quantity of nicotine or its metabolite cotinine in blood, urine, saliva, or sometimes hair; to determine whether someone uses products containing tobacco or nicotine or has been exposed to secondhand smoke; sometimes performed to evaluate for acute nicotine poisoning
Nicotine and Cotinine
Whenever someone requires confirmation of tobacco or nicotine usage or exposure to secondhand smoke; occasionally when nicotine overdose is suspected
Nicotine is an addictive chemical found naturally in the tobacco plant and in some manufactured products, such as some e-cigarettes and nicotine-replacement products (e.g., gum, patch). It is inhaled or ingested and subsequently absorbed into the blood. This testing detects and/or measures nicotine and its primary breakdown product (metabolite) cotinine in the blood, urine, saliva, or hair.
Nicotine is metabolized by the liver into more than 20 compounds, which are eliminated from the body in the urine. Both tobacco use and exposure to tobacco smoke can increase nicotine and cotinine concentrations in the body. Levels also rise with use of nicotine replacement products such as nicotine patches and gums, and with the use of smokeless nicotine vapor (e-cigarettes). In large amounts, nicotine can be poisonous.
Long-term smoking of tobacco products can increase the risk of developing many diseases, including lung cancer, oral cancer, COPD, stroke, heart disease, and respiratory infections. Years of smokeless tobacco use also increases the risk of developing oral cancer (cheeks, gums, and lips). Long-term tobacco use can worsen asthma and help promote blood clot formation. In pregnant women, smoking can impair growth of the developing baby and lead to low birth weight babies.
Cotinine is usually the test of choice to evaluate tobacco use or exposure to tobacco smoke because it is stable and is only produced when nicotine is metabolized. Cotinine has a half-life in the body of between 7 and 40 hours, while nicotine has a half-life of 1 to 4 hours.
Blood and/or urine cotinine tests may be ordered along 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 anabasine in someone's urine indicates that the person is actively using a tobacco product, as it is not found in commercial nicotine replacement products, such as a patch.
The presence of nicotine and/or cotinine in an individual's sample may indicate the use of tobacco or nicotine products or exposure to environmental tobacco smoke. Testing may be used in a number of situations to evaluate the possible use of tobacco products, such as in smoking cessation programs, prospective employment assessments, and evaluations of applicants for health or life insurance.
Nicotine and cotinine testing may also be ordered in cases of suspected nicotine poisoning. Acute overdoses of nicotine, such as might happen if a child ingests nicotine lozenges or gum, are relatively rare but generally require immediate medical attention.
How is it used?
Nicotine, and/or its primary metabolite cotinine, is most often tested to evaluate tobacco use. Because the use of tobacco products can greatly affect the health of individuals, companies may use nicotine/cotinine testing to evaluate prospective employees for tobacco use. Many health and life insurance companies test applicants for nicotine or cotinine as well.
Nicotine and cotinine can both be measured qualitatively or quantitatively. Qualitative testing detects the presence or absence of the substances, while quantitative testing measures the concentration of the substance. Quantitative testing can help distinguish between active smokers, tobacco users who have recently quit, non-tobacco users who have been exposed to significant environmental tobacco smoke, and non-users who have not been exposed.
Cotinine may also be measured in saliva and in hair, although hair testing is primarily used in a research setting, such as a study of non-smokers exposure to tobacco smoke.
A blood or urine nicotine test may be ordered by itself or along with cotinine if a healthcare practitioner suspects that someone is experiencing a nicotine overdose.
When a person has reported that he or she is using nicotine replacement products but is no longer smoking, nicotine, cotinine, and urine anabasine measurements may sometimes be ordered. Anabasine, an alkaloid, is present in tobacco but not in commercial nicotine replacement products. If a sample tests positive for anabasine, then the person is still using tobacco products.
When is it ordered?
Cotinine and/or nicotine testing may be ordered whenever an evaluation of tobacco use status or tobacco smoke exposure is required.
A court may order testing for child custody purposes. When a person enters a smoking cessation program, blood or urine cotinine tests may be ordered to evaluate his or her compliance. Urine, blood, or saliva testing may serve as a screen for tobacco use when someone is applying for life or health insurance.
Nicotine and cotinine are sometimes measured when someone has symptoms that a healthcare practitioner suspects may be due to a nicotine overdose. Symptoms of mild nicotine poisoning may include:
- Nausea, vomiting
More serious nicotine poisoning may result in:
- Increased blood pressure and/or heart rate, which suddenly drops
- Slowed or difficulty breathing
- Abdominal cramps
- Agitation, restlessness, or excitement
- Burning sensation in mouth
- Muscular twitching
- Seizures, convulsions
Hair testing is rarely performed in a clinical setting but may be ordered when an evaluation of longer-term tobacco use is desired.
What does the test result mean?
Nicotine and/or cotinine results may be reported as positive or negative, or as a level (e.g., nanograms per milliliter or ng/mL).
The level of nicotine and/or metabolites in a person's sample depends on a few factors, such as how much the person inhales or ingests. Also, the rate at which nicotine is metabolized and cotinine is cleared from the body varies from person to person.
When someone stops using tobacco and nicotine products, it can take more than two weeks for the blood level of cotinine to drop to the level that a non-tobacco user would have and several weeks more for the urine level to decrease to a very low concentration.
- In general, a high level of nicotine or cotinine indicates active tobacco or nicotine product use.
- A moderate concentration indicates that the person has not had tobacco or nicotine for two to three weeks.
- A lower level may be found in a non-tobacco user who has been exposed to environmental smoke.
- Very low to non-detectible concentrations may be found in people who have not used tobacco or nicotine and have not been exposed to environmental smoke or in tobacco or nicotine users who have refrained from tobacco and nicotine for several weeks.
Is there anything else I should know?
Test results based on different samples (blood, urine, saliva) are not interchangeable.
Some pesticides contain high concentrations of nicotine. This can be another source of nicotine poisoning. In fact, nicotine is itself a pesticide sometimes used in "organic" farming as an alternative to organophosphate or pyrethrinoid derivatives.
Nicotine is found not just in the tobacco plant but also in other plants in the same family. These include potatoes, tomatoes, eggplants, and red peppers. The concentration of nicotine in these plants, however, is much lower than that in tobacco. The cutoffs of the nicotine/cotinine tests have been set to discriminate dietary sources of nicotine from tobacco use and second-hand smoking.
A person's genetic makeup may influence how they metabolize nicotine. Variations in the genes that code for the CYP2A6 and CYP2B6 liver enzymes affect the rate of nicotine metabolism. (For more on this, see our article on Pharmacogenetic Tests.)
Do any forms of tobacco not contain nicotine?
Can e-cigarettes and vaping cause a positive nicotine result?
E-cigarettes and other electronic nicotine delivery systems (ENDS) use concentrated liquids that are heated to produce a vapor that is then inhaled. The concentrates may contain nicotine, nicotine and flavorings, or just flavorings. If nicotine is present in the concentrate, then it may be detected in your system. This concentrate also poses a risk for accidental nicotine poisoning. The ENDS products are currently thought to be less harmful than smoking, but the medical community is concerned about their growing popularity. Because they are relatively new, their long-term health effects have yet to be determined.