The accuracy of self-reported smoking status assessed by cotinine test strips.

We evaluated a new cotinine test strip to assess smoking status. Urine cotinine was measured using cotinine test strips and also by gas chromatographic techniques (GC) (as the reference criterion). Smoking status was assessed with a self-administered questionnaire. The cotinine test strip identified smokers with a very high level of agreement (97.3% using 100 ng/ml and 97.1% using 250 ng/ml for the cutoff point) and non-smokers with a fair-to-moderate level of agreement (74.5% using 100 ng/ml and 86.4% using 250 ng/ml for the cutoff point). These data suggest that the cotinine test strip appears to provide a reasonably accurate measure of smoking status. Since this was the first study to evaluate the cotinine test strip using the test strip prototype, larger clinical trials are needed to evaluate the validity of the cotinine test strip compared to GC measurements to confirm smoking status.