In the context of drug screening, which substance is primarily detected for marijuana use?

The detection of marijuana use in drug screening primarily revolves around the identification of 11-nor-9-carboxy-delta9-THC, commonly known as THC-COOH. This compound is a metabolite of delta-9-THC, which is the psychoactive component of marijuana. When marijuana is consumed, the body metabolizes delta-9-THC into various metabolites, and 11-nor-9-carboxy-delta9-THC is one of the most stable and long-lasting metabolites found in urine.

Standard drug tests, especially those used for employment or legal purposes, often focus on this metabolite because its presence indicates prior marijuana use and can remain detectable in the body for days or even weeks after the last use, depending on frequency of use and individual metabolism.

The other substances listed, such as codeine and benzoylecgonine, are related to different drugs (opioids and cocaine, respectively) and do not serve as markers for marijuana use. Delta-9-THC may indeed be detected, but it is the metabolite THC-COOH that is primarily used in drug screenings to confirm past marijuana consumption.