Nicotine/Cotinine

Nicotine or its 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 foetal growth and lead to low birth weight babies.

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. Some health and life insurance companies test applicants for nicotine or cotinine as well.

Nicotine and cotinine can both be measured qualitatively (test to see if present or absent) or quantitatively (measurement of the actual concentration). 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 exposure of non-smokers to tobacco smoke.

Nicotine or cotinine testing may be performed if a doctor suspects that someone has had a nicotine overdose.

When a patient has reported that they are using nicotine replacement products but are no longer smoking, nicotine, cotinine, and urine anabasine measurements may sometimes be requested.  Anabasine is present in tobacco but not in commercial nicotine replacement products. If a sample tests positive for anabasine then the person is likely to be still using tobacco products.

Cotinine and/or nicotine may be requested whenever an evaluation of tobacco use status or tobacco smoke exposure is required. When someone enters a smoking cessation programme, blood or urine cotinine tests may be requested to evaluate compliance. Urine, blood, or saliva testing may be performed as a screen for tobacco use when someone is applying for life insurance or health insurance, or applying for work with an employer that prohibits smoking.

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

• Feeling sick
• vomiting
• Dizziness
• Drooling
• Weakness

More serious nicotine poisoning may result in:

• Increased blood pressure and/or heart rate which then suddenly drops
• Slowed or difficult breathing
• Seizures
• Coma

Hair testing is rarely performed in a clinical setting but may be requested when an evaluation of tobacco use is desired.

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 way a person smokes - such as how deeply they inhale.  Concentrations are higher in urine than in blood or saliva.  There is also some variability from person to person and some genetic differences in the rate that nicotine is metabolized, and in the rate that cotinine is removed 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-detectable 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. 

Patients in whom nicotine overdose is self-evident would not normally 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.

Test results based on different samples (blood, urine or saliva) are not interchangeable.

Some pesticides contain high concentrations of nicotine. This can be another source of nicotine poisoning.

Nicotine is not only found in the tobacco plant, but also in other plants of the same family including potatoes, aubergines, tomatoes and red peppers. The amount of nicotine in these plants is much lower than the level in tobacco, and the cut-off values of the nicotine/cotinine tests have been set to ensure that levels of nicotine in the normal diet do not produce positive tests.

A person's genetic makeup may influence how they metabolise nicotine.  Variations in the genes that code for the CYP2A6 and CYP2B6 liver enzyme affect the rate of nicotine metabolism (for more on this see Pharmacogenomics).

No, they all contain nicotine.  This includes pipe tobacco, cigars, snuff, chewing tobacco, e-cigarettes, etc.  If you use any of these, nicotine may be detected in your system.