Nicotine can be detected through various tests that measure the level of a chemical called cotinine. The body produces cotinine only when nicotine enters the body, such as through the use of cigarettes, pipe tobacco, snuff, cigars or chewing tobacco. Cotinine can be detected by testing a person's blood, hair, saliva or urine. The results of the tests can show whether a person is a current tobacco user or former user.
There are various reasons why nicotine testing might be performed. Parents sometimes use the tests to determine whether their children have been smoking. Some companies' health insurance providers require nicotine testing to evaluate a potential employee’s health risks. Testing also can be used in smoking cessation programs, in child custody cases, when a person is applying for life insurance or for research purposes.
A urine test is a commonly used method for nicotine testing. The level of cotinine in the urine is measured by using a test strip or placing a few drops of urine onto a test disc. Urine containing cotinine reacts with the testing materials to show a positive or negative result. Home drug test kits are readily available at pharmacies or through the Internet for those who want conduct nicotine testing privately. A nicotine urine test is valid for about four days after a person last used tobacco.
Evaluation of saliva for nicotine testing is a process similar to the urine test. For this assessment, a saliva sample is placed onto a test strip and produces results in about half an hour. Although the nicotine saliva test gives consistent and accurate results, it might show a positive reading from exposure to secondhand smoke. Parents sometimes use saliva home test kits to determine whether their children have been smoking.
Blood analysis for nicotine testing is not as reliable as urine or saliva tests. When a person uses tobacco, the blood level of nicotine rises almost immediately and remains present for more than two weeks. The level of nicotine shown in the blood can vary depending on the individual’s metabolism, the type of tobacco used and how deeply smoke is inhaled. Some employers prefer blood evaluation because they can check for nicotine and illegal drugs at the same time.
Cotinine can remain in hair follicles for up to a year after a person has stopped using tobacco. Nicotine testing with hair samples is costly and is rarely used by insurance companies or employers. It is generally confined to research that measures the effects of secondhand smoke on non-smokers. Hair from any part of the body is suitable for this type of test.