Nicotine is a hygroscopic alkaloid obtained from tobacco. Cotinine is the major metabolite of nicotine.
Normal range (serum): Cotinine
Nonsmokers: <6 ng/mL
Cigarette smokers: 10 " “50 ng/mL
Use
Insecticide and fumigant
Constituent of tobacco products
Constituent of smoking cessation products
Interpretation
Serum cotinine concentrations may be up to 10 times greater than corresponding nicotine level in smokers.
Urine nicotine and cotinine concentrations in smokers are typically >1,000 ng/mL.
Limitations
Screening tests are immunoassay based typically target cotinine with a cutoff concentration of 100 " “500 ng/mL (for urine). Test may cross-react with 3-hydroxy cotinine.