Can a urine test tell if you are taking narcotic as prescribed?

Yes, Urine drug test. They can test also your blood, saliva and hair. For example 5 panel drug test ("SAMHSA 5" previously called the "NIDA-5") check for : Cannabinoids (marijuana, hash) /Cocaine (cocaine, crack, benzoylecognine) /Amphetamines (amphetamines, methamphetamines, speed) /Opiates (heroin, opium, codeine, morphine) and PCP (Phencyclidine)