Marijuana is the most commonly used illegal drug in the United States. It is not a surprise that law enforcement is concerned about legal marijuana use and driving while under the influence of legal marijuana. In typical political fashion, the legislature in Colorado authorized medical marijuana and then realized the problem they had created. The problem for Courts, prosecutors and a defense attorney is what does DUID (driving under the influence of drugs) mean? DUI says that you were substantially incapable of of the safe operation of a motor vehicle due to the influence of alcohol, drugs or both alcohol and drugs. We know the 0.08 DUI rule for alcohol but for marijuana we have no bright line rule for active THC (I was involved in stopping the 5 ng limit proposal). Furthermore, we have two separate blood test results for marijuana THC and THC-COOH, both measured in NG.
THC and THC-COOH
THC is the active THC in your blood (think how much alcohol is in your system for a DUI blood test). The THC-COOH is a test for the amount of inactive metabolite of THC in your blood (think if we had a blood test to determine how much alcohol you have drank over the last 30 days – but has nothing to do with how much alcohol is in your system at the time of driving). The THC-COOH is only used to prove that a person has used marijuana in the past. THC is not an easy drug to measure. Furthermore the Colorado Department of Public Health method of testing is also up for debate about accuracy. Blood tests have a second sample that we can have tested at a private facility. I have seen huge discrepancies (i.e. getting a DUID case dismissed) between the State test results v. private (more accurate) re-tests (6 ng v. 1 ng / 8 ng v. 4 ng). The point is: understand how to read the test and then consider a strategy that is best for you.