Contingency management for smoking cessation: enhancing feasibility through use of immunoassay test strips measuring cotinine.

Contingency management (CM) is a powerful behavioral intervention shown to reduce the use of a variety of substances including tobacco. Use of CM techniques for smoking cessation has been restricted by the use of multiple daily measurements of breath CO as the objective indicator to reinforce abstinence. Cotinine, with its longer half-life, may be a better marker. We evaluated the use of urinary cotinine (determined using once-daily semiquantitative immunoassay test strips and verified using quantitative GC/HPLC techniques) as an abstinence indicator in treatment-seeking adult and adolescent smokers participating in a CM-based intervention program. Both techniques of determining urinary cotinine were highly sensitive and moderately specific at detecting abstinence, and they were highly concordant. However, specificity was somewhat lower during the first few days of a quit attempt and improved over time. The results were similar in adults and adolescent smokers, and suggest that during the first few days of a quit attempt it would be advisable to continue to use daily multiple CO measurements to verify abstinence. However, once abstinence is achieved, once-daily immunoassay test strips could be used for continued monitoring of urinary cotinine levels. Immunoassay testing can identify individuals who relapse to smoking, though this study cannot evaluate whether the strips can identify resumption of abstinence. These results suggest that the use of cotinine as an abstinence indicator, by reducing the number of daily appointments, could significantly enhance the feasibility and utility of CM-based interventions for smoking cessation.