When a person smokes tobacco, nicotine enters the body, which, in turn, creates a byproduct called cotinine. Whether you are a heavy smoker, a light smoker or are exposed to cigarette smoke on a regular basis, the presence of cotinine can be detected in your blood, urine, saliva and hair. Tests may be carried out by employers and medical insurance companies because of the health risks associated with smoking tobacco.
Blood will be taken from a vein in your arm and tested for the presence of cotinine. According to the Foundation for Blood Research, cotinine levels of less than 10 units indicate that you are not a smoker, and the average cotinine levels of a smoker range from 150 to 450 units. Receiving your blood test results will normally take around two to seven days.
You will be asked to deposit a sample of your urine which will be tested for levels of cotinine. The levels of cotinine if a person is smoking is occur in much higher concentrations in the urine than other tests, and it can be tested up to four days after smoking and still detect the chemical. This makes it a popular choice for testing whether someone is smoking, detecting concentrations up to ten times higher than a blood test.
A swab will be taken from your mouth using a q-tip which will absorb a sample of your saliva to test for cotinine and its concentrations. Like with the blood test, a level of 10 units or less indicates a negative result, and that you are not smoking.
Hair Follicle Test
A less common but highly effective method of testing is done by taking a sample of your hair and testing it for the presence of cotinine. This hair test can be done up to 90 days after smoking to achieve an accurately positive result and likewise can give a more reliable indication that someone does not smoke, indicating the person has not just stopped smoking to avoid a positive test result.