Remote biochemical verification of tobacco use: Reducing costs and improving methodological rigor with mailed oral cotinine swabs

Multi-site tobacco cessation trials could benefit from remote biochemical verification for tobacco use without invasive, time-consuming, or expensive collection processes. To the authors' knowledge, there have been no previous studies examining the predictive validity of oral fluid swabs for the detection of cotinine levels with samples collected off-site and mailed for on-site interpretation. Tobacco users were recruited through an online...