THC remains in the bloodstream up to 28 days compared to alcohol which can be gone in 12 hours or less unless you need a drink when you get out of bed. THC pre

THC remains in the bloodstream up to 28 days compared to alcohol which can be gone in 12 hours or less unless you need a drink when you get out of bed. THC presence could be as much as 56 times likely to show as alcohol. You really need to know the THC (and any other drug) level before you can determine impairment.