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Smoking and Tobacco

Nicotine Presence in Blood and Urine



I quit smoking on March 19, 2006. I have had 4 drags of cigarettes since then, the last being on July 20, 2006. I had a blood and urine test taken on Nov. 21, 2006 for life insurance. It came back that I was a smoker. How long do I have to "Quit" before this no longer shows in blood and urine test? I was very shocked this still showed in my system. I was in a smokey bar 4 days before the test...could this have caused the positive test?


That is possible if the bar was extremely smoky. I assume you were not using any nicotine replacement product, like the patch, etc. which would deliver nicotine to the system.

According to Dr. Mary Ellen Wewers, Professor & Associate Dean for Research, Interim Director, Center for Health Outcomes, Policy and Evaluation Studies (HOPES), The Ohio State University, School of Public Health:

"Nicotine has a short half-life (2-4 hours) so often it is not detectable after 24 hours. Cotinine, its major metabolite, has a half-life of 16-19 hours, so it usually is detectable for 4-7 days, depending upon amount of consumption." Cotinine can be detected in the urine and saliva as well.

Your question is addressed in the Cotinine Testing Patient Information Sheet from the Foundation for Blood Research:

Q: What about other people's smoke? Won't my cotinine level increase if I breathe other people's smoke?

A: If you breathe a lot of cigarette smoke even though you yourself don't smoke, your cotinine level may be higher than that of a non-smoker. If so, you should try to avoid places where there is a lot of smoke.

Sources for information on Cotinine are:

(See the CDC's Fourth National Report on Human Exposure to Environmental Chemicals)

For more information:

Go to the Smoking and Tobacco health topic, where you can:

Response by:

Kathy Vesha, RN, BSN, MA
Kick It!
The James
The Ohio State University