Testing for Smoking and Tobacco Use

It is now relatively easy to check if somebody has been smoking cigarettes or tobacco products. Tobacco use is very often evaluated with a nicotine/cotinine test.

Why Tobacco Use Is a Concern

Prolonged use of tobacco products can lead to increased risk of developing several diseases like heart disease, lung cancer, stroke and respiratory tract infections, or even worsen blood clotting and asthma. Pregnant women who smoke tobacco are exposed to the risk of foetal growth retardation which can lead to birth of babies with low weights.

Since the use of tobacco products can have great effect on individual’s health, nicotine/cotinine tests can be used by companies to detect tobacco use by prospective employees. There are also some life and health insurance companies which test applicants for nicotine or cotinine (nicotine metabolite).

How We Test for Nicotine

When testing for smoking, we can measure both Nicotine and Cotinine quantitatively and qualitatively. Qualitative testing is used to detect the presence or absence of nicotine/cotinine while quantitative testing is used to measure the concentration of nicotine/cotinine. Quantitative testing can help to distinguish between the following sets of people:

  • Active smokers;
  • Tobacco users who quit smoking recently;
  • Non-tobacco smokers who have suffered from significant exposure to tobacco smoke in their environment;
  • Non-tobacco users who have suffered no exposure at all.

We can also measure cotinine in the hair or saliva, although hair testing is used mainly for research purposes such as in the study of non-smokers’ exposure to the smoke of tobacco.

A doctor may perform nicotine/cotinine testing if somebody is suspected to have had an overdose of nicotine.

How Do I Interpret the Nicotine Test Result?

The levels of nicotine in the blood can rise sharply in just a few seconds of puffing a cigarette. The quantity of the nicotine in the blood is dependent on that in the cigarette and how the person smokes, for instance, how deeply he or she inhales.

The concentration of nicotine in urine is higher than that in the saliva or blood. The levels of nicotine in the blood also vary from one individual to another and also depend on some genetic variations relating to the rate of nicotine metabolism, and on the rate of removal of cotinine from the body.

When you quit tobacco smoking and other related nicotine products, the cotinine levels in your blood can take over 2 weeks to drop to those of a non-tobacco user and a couple of weeks more for the cotinine concentrations in your urine to drop.

Generally, nicotine/cotinine high levels are an indication of active use of nicotine or tobacco replacement. Medium concentrations are an indication that a user of tobacco has not taken tobacco or nicotine for 2-3 weeks. Lower nicotine/cotinine levels may be detected in a person who does not use tobacco but suffers from environmental smoke exposure. Very low levels and untraceable concentrations are detected in non-users of tobacco who do not suffer from environmental smoke exposure or users who, for a couple of weeks, have avoided nicotine and tobacco.

What Else Should I Know?

You cannot interchange test results which are based on different samples of urine, blood or saliva.

It is not only in tobacco plant that you find Nicotine; you can also find it in some other plants in the same family, for example, aubergines, potatoes, red peppers and tomatoes. The quantity of nicotine in the above-mentioned plants is very much less than that in tobacco and it has been ensured that the nicotine levels in a normal diet cannot test positive by simply setting threshold values for the levels.

Photo Credit: “Lost in My Thoughts” (CC BY 2.0) by jstimp

This post has been updated since its original publication in 2013.