Cotinine is the major inactive metabolite of nicotine and a stable biomarker of tobacco and nicotine exposure. With a 15 to 20 hour half-life (versus about 2 hours for nicotine), it provides a reliable measure of recent use, useful for cessation support, preoperative assessment, and prenatal and addiction care.³

Confirming smoking status matters clinically: preoperative cessation improves wound healing and reduces pulmonary complications,¹ and cessation in pregnancy reduces complications.² A cotinine result gives an objective measure that self-report may not.

Cotinine is measured by immunoassay and reported semi-quantitatively, with a 300 ng/mL cutoff; active tobacco use generally produces levels above 1,000 ng/mL.³ The test detects nicotine from any source, so patients using replacement gum or patches, or vaping, will also be positive. It cannot identify the product or quantify exposure precisely.

• Use cotinine to objectively assess smoking status when self-report is insufficient.²
• Interpret against the 300 ng/mL cutoff; active use generally exceeds 1,000 ng/mL.³
• Account for nicotine replacement and vaping, which also test positive.
• Time preoperative testing close to surgery to gauge cessation success.¹
• Recognize secondhand exposure usually yields low-level results.