What are the Benefits of Knowing Urinary Cotinine Levels

All tobacco products contain nicotine. Nicotine is just one over over 4,000 chemicals contained in cigarette, cigar, and pipe smoke. Nicotine is a highly addictive chemical and one of the reasons that quitting smoking is so difficult (1). Nicotine is metabolized in cotinine. This chemical is found in the blood, hair, and urine, after smoke exposure. Cotinine can be detected in the urine for about 2 to 4 days after exposure to tobacco smoke (2). This depends on the amount and duration of the smoke exposure.

The usefulness of measuring urinary cotinine levels are:
1. to determine if some one is still smoking, especially when he or she are trying to quit smoking. The levels correlate roughly with the amount of smoking, but there is large variability between persons.
2. to determine if some one is getting second-hand smoke exposure. This has been used in legal cases where custody and care are being disputed. The lab companies, such as LabCorp, are reluctant for the test to be used for the reason above and because they could drawn into the dispute. Nevertheless, this can be used with caution. Where and who the smoke came from may be disputed. A very careful amount of testing can limit the theoretical options.

For example, let's say that the child lives with parent 1, who also provides regular medical care to the child. If the child keeps getting respiratory illnesses after spending weekends with parent 2, then it would be reasonable to wonder if the child is exposed to something, such as second-hand smoke, at parent 2's home. This would be detrimental to the child's health, not to mention be very aggravating for the parent 1, who has to take care of the sick child during the week, only to have the child become ill again in the same pattern. In this example, if cotinine levels are to be used, then a combination approach may be useful. Parent 1 should document by testing that his or her cotinine level is 0 by serum and urine tests the day that the child goes to parent 2. The child's urine cotinine level, by serum and urine tests, should be measure on the same day. Ideally, the cotinine levels of parent 2 and the child would be measured, although I have never seen a parent 2 cooperate. On the day the child returns, the cotinine levels of parent 1 and the child should be measured again by two methods. This approach would show that no smoke exposure occurs at parent 1's home and that the child was exposed to smoke (hopefully second-hand) when away from parent 1's home. The disadvantage of this is that it can be expensive, the levels do vary, and be time consuming. Courts in my opinion take the issue of second-hand smoke exposure and resulting illness rather lightly. Nothing may come of this, but it's an optional approach.

I am exposed to various permutations of this scenario frequently. My focus remains what is best for the child's health. I try to support what ever support system that provides good medical care and I try to discourage any behaviors that damage the child's health. This has brought me into conflict with many parents. While being as professional as I can, I insist that the lower the child's smoke exposure, the healthier the child will be.

If you have questions about urinary cotinine levels, ask your doctor...