Problems with thiocyanate as an index of smoking status: a critical review with suggestions for improving the usefulness of biochemical measures in smoking cessation research.

The purpose of this paper is to present a comprehensive review of the literature on SCN in order to illustrate the methodological issues involved in using biochemical indices of behavior. We discuss issues related to the sensitivity, specificity, predictive value, and reportedly long half-life of SCN. We also briefly discuss how these issues relate to other biochemical indices of smoking. We conclude with suggestions for improving the measurement of smoking status.