Urine drug screening Health Article

Definition

Urine drug screening, or toxicological screening, is a process of chemical analysis designed to test patients for drug abuse, or to insure that a patient is substance-free before undergoing a medical procedure.

Description

Urine drug screening can be used to evaluate possible accidental or intentional overdose or poisoning, to assess the type and amount of prescribed and/or illicit drugs used by a person, or to determine the cause of acute drug toxicity. It is also used to monitor drug dependency or to determine the presence of drugs in the body for medical and legal purposes.

In many occupations, urine drug screening has become a required condition of employment. Nearly all workers in certain occupations, such as law enforcement and transportation, must submit to periodic, random, and post-incident drug screening. Federal laws mandate the administration of drug screens to workers in the transportation industry, including bus drivers, truckers, airline employees, and railroad workers. Federally required testing must be conducted by a laboratory certified by the Substance Abuse and Mental Health Services Administration. Other industries must follow state regulations, which vary considerably.

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. Preliminary urine screening results, when positive, should be confirmed by a more accurate method that can distinguish between poppy seed ingestion and use of heroin or other opiates. Poppy seeds and opiates produce different chemicals, known as metabolic breakdown products or metabolites, as they travel through the body, allowing them to be distinguished from one another.