How Long Can Tobacco Smoke be Detected with a Nicotine & Metabolite Serum Test?
- In active tobacco users, average nicotine levels range from 30 ng/mL (nanograms per milliliter) to 50 ng/mL. Nicotine is metabolized by the liver to produce the chemical cotinine (an anagram of nicotine). While nicotine has a short half-life, cotinine is metabolized in the system at a much slower rate.
- A nicotine and nicotine metabolite test measures nicotine and its metabolite cotinine in the system. It is with both these values that determination of nicotine usage can be made.
- In heavy tobacco users, nicotine and cotinine levels in serum reduce after two weeks of abstinence to less than 2 ng/mL. This measurement is the standard in determining non-usage. Levels higher than 2 ng/mL indicate the test subject might be continuing to use tobacco or has been exposed to secondhand smoke.