Urine screening tests are able to detect general classes of compounds, such as amphetamines, barbiturates, benzodiazepines, and opiates. Drug screening can also detect cocaine, marijuana, and phencyclidine (PCP). The screening tests themselves are unable to distinguish between illicit and prescription drugs within the same class. A patient taking prescribed codeine pills and an individual using heroin would both show positive urine screening tests for opiates. It is also possible for some over-the-counter medications to cause a positive drug screen in someone who has taken neither illegal nor prescription drugs. These incorrect reactions are known as "false-positives." Urine drug screens can detect the use of several drugs. Some of these drugs are as follows: cocaine amphetamines heroin morphine phencyclidine (PCP) benzodiazepines alcohol hydromorphone tetrahydrocannabinol (THC) propoxyphene methadone codeine barbituates Certain foods, such as poppy seeds, may result in a positive urine screen for opiates, since poppy seeds are derived from opium poppies. my advice is if you are doing drugs get clean for about 2 months then try again. Now, not everyone uses urine tests, they do hair folical tests and lets just say they go back along time.