Evaluation of Urinary Cotinine Immunoassay Test Strips Used to Assess Smoking Status

Abstract

Validation of smoking status is a vital component for assessing self-reported smoking status. This study examined commercially available urinary cotinine immunoassay strips to evaluate their effectiveness and their reliability in validating self-reported tobacco usage. This study compared cotinine values from urinary test strips and liquid chromatography-mass spectrometry (LC-MS/MS) obtained from 100 self-reported nonsmokers and 201 self-reported smokers. The analyzed test strips, with 100 ng/ml as the cutoff value, have 91% (84%-96% CI) specificity and 92% (86%-95% CI) sensitivity. The test strips successfully identified nonsmokers from smokers with excellent reproducibility. However, self-reported smokers have significantly different (p < .001) test strip results when compared with the expected LC-MS/MS values. Overall, the test strip demonstrated that it discriminates nonsmokers from smokers and is an adept alternative to chromatographic methods.