The most commonly utilized chemical test for a marijuana after a DUI arrest is a urine test. In most of California typically a suspect detained for DUI will be required to submit to either a breath or blood, but when drugs such as marijuana are suspected the choice is restricted to blood or urine. Because most people will choose to take a leak in a cup over having a sharp needle jabbed in their arm, the most common test seen is that of urine. Problems can come into play with marijuana urine tests. The most often asked inquiry is how long does marijuana stay detectable in a persons urine?
It is commonly accepted in the scientific community that cannabis metabolite (a breakdown product) is detectable in urine for an extended period of time compared to other drugs. Initially, it is important to define what is meant by marijuana metabolite. Very often this term refers to a specific breakdown product of cannabis called delta-9-carboxy-tetrahydrocannabinal (otherwise known as THC). What is crucial to understand in the context of DUI prosecutions is that carboxy THC is not psychoactive and has no effect on ones physical performance or ability to drive an automobile safely. Carboxy THC is an oily substance that accumulates in a person's body fat over time after smoking and is slowly released into the blood and excreted into the urine as a waste product.
This is the main reason why carboxy THC is detectable in the urine for extended periods of time compared to that of other substances and their metabolites. Since the effects of pot seldom last beyond several hours, the presence of carboxy THC in the urine sample collected after an arrest for DUI does not necessarily prove that the individual was DUI or impaired by the recently smoked pot at the time of driving his or her motor vehicle.