There was a time when marijuana was illegal everywhere and testing for it was as easy as could be.
It didn’t matter the level of cannabinoids found in a person’s body. If it was there, they were breaking the law.
It’s different now.
The tests have changed from depositing a urine sample into a cup to drawing blood or offering oral fluids. Also different is the particular type of cannabinoid — the chemical compound that reacts in the brain — detected by any of those tests.
The evolving science of testing for marijuana, and the lack of consensus over how to measure impairment, is a…