Fig. 3.

Effect of adding toxicology testing for THC at various cutoffs (ng/mL) to determinations of impairment based solely on FSTs at various timepoints after smoking. The shaded area refers to where the specific toxicology cutoffs are applied to FSTs Exam #1 (71 minutes post-smoking); the unshaded area represents FSTs Exam #3 results (188 minutes post-smoking) combined with specific toxicology cutoff concentrations. Dashed lines indicate time of the FSTs. (A), Percent of active drug group classified as impaired and exceeding specific blood cutoff concentrations; (B), Percent of placebo group classified as impaired and exceeding specific blood cutoff concentrations; (C), Percent of active drug group classified as impaired and exceeding specific oral fluid cutoff concentrations; (D), Percent of placebo group classified as impaired and exceeding specific oral fluid cutoff concentrations.