Cotinine is the major breakdown product of nicotine, with a longer half‑life, making it a reliable marker of tobacco exposure.

Clinical uses include:

Detecting active smoking.

Assessing passive exposure to tobacco smoke.

Monitoring smoking cessation programs.

Supporting clinical trials and occupational health assessments.

More sensitive and specific than direct nicotine measurement.

Often performed alongside blood cotinine or saliva cotinine tests for confirmation.

Analyte: Cotinine in urine (ng/mL).

Normal Range (varies by lab):

Non‑smokers: <10 ng/mL.

Passive exposure: 10–100 ng/mL.

Active smokers: >100 ng/mL.

Abnormal Findings:

Elevated cotinine indicates recent nicotine exposure (usually within the past 2–3 days).

Clinical Use:

Provides a direct biochemical marker of tobacco exposure.

Helps guide smoking cessation, public health monitoring, and occupational safety programs.

Supports pulmonology, cardiology, and preventive medicine evaluations.