Cotinine in Serum/Plasma (24-hour urine collection)

Why Is This Test Done?

Your healthcare provider may order this test if you’re trying to quit smoking, managing nicotine addiction, or evaluating exposure to nicotine. It can also help confirm whether you’ve followed instructions for a nicotine reduction plan, such as using nicotine replacement therapy.

How Is the Test Performed?

For a 24-hour urine test, you’ll collect all urine over a full day in a special container. For serum/plasma, a blood sample is taken from a vein. The sample is then sent to a lab for analysis using a sensitive immunoassay method to detect cotinine levels.

What Do Results Mean?

Higher cotinine levels suggest recent nicotine exposure, while lower levels may indicate reduced or no smoking. However, results alone don’t confirm smoking status—your provider will interpret them alongside other factors like symptoms or medical history.

What Are Possible Results?

Results are typically reported in micrograms per milliliter (µg/mL) for serum/plasma or milligrams per liter (mg/L) for urine. Interpretation depends on clinical context, such as whether the test is part of a smoking cessation evaluation.