Current Cutoff Levels for Toxicology
**Clinical Chemistry 48:9 1460-1471, 2002**
Unexposed non-tobacco user: Nicotine <2 ng/mL; Cotinine <2 ng/mL; 3-hydroxycotinine < 2ng/mL
Passive exposure: Nicotine <2 ng/mL; Cotinine <8 ng/mL; 3-hydroxycotinine < 2ng/mL
Abstinent user for more than 2 weeks: Nicotine <2 ng/mL; Cotinine <2 ng/mL; 3-hydroxycotinine < 2ng/mL
Active tobacco product user: Nicotine 30-50 ng/mL; Cotinine 200-800 ng/mL; 3-hydroxycotinine 100-500 ng/mL