Workplace drug testing was started as an effort to suppress workers from using controlled substances on the job. It has, by and large, failed, especially in the case of Marijuana. Metabolites from Cannabis are fat soluble. That means that long after the “High” is gone, non-psychoactive metabolites can be detected in bodily fluids. At the time of this writing, there is no test that accurately and reliably identifies a person as currently “Under the influence” of Marijuana.
Legalization is coming. Employers, courts and insurance companies need to understand why testing for Marijuana is ineffective, and soon to be unnecessary at all.