Nicotine / Cotinine
At a Glance
Why Get Tested?
To detect the presence of and/or measure the quantity of nicotine or cotinine in blood, urine, saliva, or sometimes hair; to determine whether someone uses tobacco or has been exposed to secondhand smoke; sometimes performed to evaluate for acute nicotine poisoning
When to Get Tested?
Whenever someone requires confirmation of tobacco usage or exposure to secondhand smoke; occasionally when nicotine overdose is suspected
Sample Required?
A blood sample collected from a vein in your arm or a random urine sample; sometimes a saliva sample or, rarely, a hair sample
Test Preparation Needed?
None
The Test Sample
What is being tested?
Nicotine is an addictive alkaline chemical found in the tobacco plant and concentrated in its leaves. It is inhaled with each puff on a cigarette and ingested with chewing tobacco. Nicotine is metabolized by the liver into more than 20 compounds, which are excreted by the kidneys into the urine. Both tobacco use and exposure to tobacco smoke can increase nicotine and its primary metabolite, cotinine, concentrations in the body. Levels also rise with nicotine replacement products such as nicotine patches and gums. In large amounts, nicotine can be poisonous.
Cotinine is the major metabolite of nicotine and 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 nicotine and/or cotinine in an individual's sample may indicate the use of tobacco 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. Symptoms can include a burning mouth, nausea, abdominal pain, salivating (drooling), diarrhea, sweating, confusion, dizziness, agitation, increased heart rate, rapid or difficult breathing, convulsions, coma, and even death.
How is the sample collected for testing?
A blood sample is obtained 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, directly or by soaking a collecting cloth or swab with saliva. Rarely, a hair sample may be collected.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
The Test
How is it used?
Nicotine or its primary metabolite cotinine are most often tested to evaluate 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 exacerbate asthma, and blood clot formation. In pregnant women, smoking can retard fetal growth and lead to low birth weight babies.
Because 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. 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.
Blood or urine nicotine may be ordered by itself or along with cotinine if a doctor 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 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 may be ordered whenever an evaluation of tobacco use status or tobacco smoke exposure is required. When a person enters a smoking cessation program, blood or urine cotinine tests may be ordered to evaluate compliance. Urine, blood, or saliva testing may be performed as a screen for tobacco use when someone is applying for life or health insurance, or applying for work with an employer that prohibits smoking. Testing may also be ordered by a court for child custody purposes. Since smoking can increase the risks of medical complications, testing may be performed prior to the start of some drug therapies or surgical procedures.
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 may include:
- Nausea, vomiting
- Dizziness
- Drooling
- Weakness
More serious nicotine poisoning may result in:
- Increased blood pressure and/or heart rate, which then suddenly drops
- Slowed or difficulty breathing
- Seizures
- Coma
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?
In the blood, nicotine levels can rise within a few seconds of a puff on a cigarette. The quantity depends on the amount of nicotine in the cigarette and the manner in which a person smokes, such as how deeply they inhale. There is also some variability from person to person and some genetic differences in the rate at which nicotine is metabolized and in the rate at which cotinine is cleared from the body. When someone stops using tobacco and nicotine products, it can take more than two weeks for blood levels of cotinine to drop to the level that a non-tobacco user would have and several weeks more for urine levels to decrease to very low concentrations.
In general, high levels of nicotine or cotinine indicate active tobacco or nicotine replacement use. Moderate concentrations indicate a tobacco user who has not had tobacco or nicotine for two to three weeks. Lower levels may be found in a non-tobacco user who has been exposed to environmental smoke. Very low to non-detectible concentrations are found in non-tobacco users who have not been exposed to environmental smoke or a tobacco user who has refrained from tobacco and nicotine for several weeks.
When a nicotine overdose is self-evident, the person may not be tested for nicotine or cotinine. Concentrations would typically be increased, but levels do not necessarily correlate with the severity of a person's symptoms.
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.
Nicotine is found not just in the tobacco plant but also in other plants in the same family, including potatoes, tomatoes, eggplants, and red peppers. The concentration of nicotine in these plants, however, is much lower than the level in tobacco. The cutoffs of the nicotine/cotinine tests have been set to discriminate between dietary sources of nicotine and those 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).
Common Questions
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Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Arup Consult. Nicotine & Metabolites. Available online at http://www.arupconsult.com/Topics/NicotineMetabolites.html#tabs=0 through http://www.arupconsult.com. Accessed Nov 2010.
Medicinenet.com. MedTerms: Nicotine. Available online at http://www.medterms.com/script/main/art.asp?articlekey=22807 through http://www.medterms.com. Accessed Nov 2010.
Sources Used in Previous Reviews
Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 1326-1327, 1422-1425.
Perez, E. (2007 January 19, Updated). Nicotine. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/002510.htm. Accessed on 9/9/07.
Wilson, S. et. al. (2007 April 10). The Role of Air Nicotine in Explaining Racial Differences in Cotinine Among Tobacco-Exposed Children. Medscape from CHEST 2007;131(3):856-862 [On-line information]. Available online at http://www.medscape.com/viewarticle/554042 through http://www.medscape.com. Accessed on 9/9/07.
Barclay, L. (2007 July 20). Comprehensive Smoking Bans May Decrease Secondhand Smoke Exposure. Medscape Medical News [On-line information]. Available online at http://www.medscape.com/viewarticle/560150 through http://www.medscape.com. Accessed on 9/9/07.
(2007 February). Nicotine and Related Compounds in Urine and Serum/Plasma. ARUP Technical Bulletin [On-line information]. PDF available for download through http://www.aruplab.com. Accessed on 9/9/07.
(1999-2000). Cotinine. CDC Laboratory Procedure Manual [On-line information]. PDF available for download at http://www.cdc.gov/nchs/data/nhanes/frequency/lab06_met_cotinine.pdf through http://www.cdc.gov. Accessed on 9/9/07.
(2006 July). Nicotine Replacement Therapy. American Lung Association, Nicotine Replacement Therapy [On-line information]. Available online at http://www.lungusa.org/site/apps/s/content.asp?c=dvLUK9O0E&b=34706&ct=66696 through http://www.lungusa.org. Accessed on 10/6/07.
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition]. Pp. 1299-1300.
Boulton, M., et. al. Reported (2003 May 9). Nicotine Poisoning After Ingestion of Contaminated Ground Beef --- Michigan, 2003. CDC MMWR [On-line information]. Available online at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5218a3.htm through http://www.cdc.gov. Accessed on 10/6/07.
Michigan Department of Community Health. Nicotine Factsheet [On-line information] PDF available for download at http://michigan.gov/documents/Nicotine_Factsheet_82361_7.pdf through http://michigan.gov. Accessed November 2007.
