What does a cotinine urine test detect?

What Does a Cotinine Urine Test Detect?

Cotinine is a chemical compound that is a byproduct of nicotine metabolism. It is utilized as a biomarker to detect tobacco use and exposure to tobacco smoke. When nicotine enters the body, it is metabolized in the liver where it is converted to cotinine. Cotinine has a longer half-life than nicotine, making it a reliable indicator of tobacco use.

Table of Contents

  1. Introduction
  2. Principle of Cotinine Urine Test
  3. Clinical Significance
  4. Test Procedures and Parameters
  5. Interpretation of Results
  6. Company Solutions
  7. References

Introduction

The presence of cotinine in urine is a key indicator used by healthcare providers to assess tobacco exposure. Given its longer half-life, cotinine can be detected in urine for up to 7 days following exposure to nicotine. This makes it a valuable tool for smoking cessation programs, insurance assessments, and clinical studies.

Principle of Cotinine Urine Test

The cotinine urine test is based on immunoassay techniques, such as Enzyme-Linked Immunosorbent Assay (ELISA) or more specific chromatographic methods like Gas Chromatography-Mass Spectrometry (GC-MS). These tests measure the concentration of cotinine in urine to a degree of precision necessary for clinical diagnostics.

Clinical Significance

Cotinine levels in urine correlate with the degree of nicotine exposure:

  • Non-smokers: < 10 ng/mL
  • Light smokers or passive exposure: 10 - 100 ng/mL
  • Active smokers: > 100 ng/mL

These results can aid in distinguishing between active smokers, passive exposure, and non-smokers.

Test Procedures and Parameters

Standard urine cotinine tests involve the collection of a urine sample, which is then analyzed using either immunoassay or chromatographic methods. Key parameters include:

  • Sensitivity: As low as 5 ng/mL for advanced immunoassays.
  • Specificity: GC-MS provides near 100% specificity.
  • Time to Result: Typically, 24 to 48 hours depending on the method.

Interpretation of Results

A positive test result signifies exposure to nicotine, whether through direct smoking or secondhand smoke. Clinicians must consider potential variables such as diet, metabolism, and potential cross-reactivity with other substances.

Company Solutions

Leading companies offering cotinine urine test solutions include:

  • LabCorp: Provides comprehensive testing services, including both standard and expanded panels for cotinine detection.
  • Quest Diagnostics: Offers reliable immunoassay testing with detailed result interpretation.
  • Alere Toxicology: Specializes in workplace testing solutions with rapid turnaround times.

References

  1. Benowitz, N. L., et al. (2009). Biomarkers of tobacco exposure: comparison of urine and serum cotinine levels. Cancer Epidemiology Biomarkers & Prevention, 18(12), 3265-3271.
  2. Hukkanen, J., et al. (2005). Metabolism and disposition kinetics of nicotine. Pharmacological Reviews, 57(1), 79-115.
  3. Pérez-Stable, E. J., et al. (1995). Urinary cotinine levels in non-smoking adults: effects of exposure to environmental tobacco smoke. American Journal of Public Health, 85(5), 735-738.
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