Urine Drug Test

Written by Debra Stang | Published on July 25, 2012
Medically Reviewed by George Krucik, MD

What is a Urine Drug Test?

A urine drug test, also known as a urine drug screen or a UDS, is quick and painless. It tests your urine (pee) for the presence of certain illegal drugs and prescription medications. The urine drug test usually screens for alcohol, amphetamines, benzodiazepines, marijuana, cocaine, and opioids (narcotics).

A urine drug test can catch possible substance abuse problems. Once these problems are identified, doctors can help you start a treatment plan. Urine drug tests throughout the treatment help ensure that the plan is working and that you are no longer taking drugs.

When Is the Test Used?

There are several scenarios where a urine drug test might be ordered.

Your primary care doctor may order this test if he or she suspects you have a problem with drugs or alcohol. An emergency room doctor may also request this test if you are confused and your behavior seems strange or dangerous.

Many employers require potential employees to get a urine drug test before hiring them. One benefit of the urine drug screen is that it can be used to keep people with drug problems out of jobs that require the ability to be alert and focused. A drug-addicted air traffic controller or semi-truck driver, for instance, could put the safety of many people at risk.

Drug and alcohol rehabilitation centers test residents on a regular basis. This helps ensure that people receiving treatment for drug or alcohol abuse are staying sober. If you are on probation or parole for a drug- or alcohol-related offense, the officer in charge of your case may request random drug tests to verify sobriety.

Finally, the tests can be used in home settings. For instance, parents may ask teenagers to take this test to prove that they are not using drugs or alcohol. If you are planning to test your teen at home, it’s a good idea to consult with your family doctor or another health professional beforehand. He or she can advise you on how to follow up if the test is positive.

Types of Urine Drug Tests

There are two types of urine drug screens. The first, called the immunoassay, is cost-effective and gives results quickly. However, it has drawbacks. For example, it does not pick up on all opioids (narcotics). Also, it sometimes gives false positives. A false positive occurs when the test results come back positive for drugs, but no drugs have been taken.

If your first test does come back positive, but you deny drug use, you will be given a second type of test: a gas chromatography or a mass spectrometry. The procedure for getting the specimen is no different from the procedure for an immunoassay described above. These tests are more expensive and take longer to give results, but they rarely produce a false positive.

Other weaknesses common to both types of tests include:

  • false negatives (the test reports a negative result even if drug use has occurred)
  • vulnerability to cheating the system
  • failure to capture same-day drug use

How to Take the Test

You may take the urine drug test anywhere a bathroom is available—in a doctor’s office or hospital, a place of business, or at home. The test is carried out as follows:

  • The person administering the test will give you a specimen cup.
  • You will be required to leave your purse, briefcase, or other belongings in another room while you take the test. You may also be asked to change from your street clothes into a hospital gown.
  • In some cases, the nurse or technician administering the urine drug screen will accompany you into the bathroom so that you cannot do anything to skew the test results.
  • Clean your genital area with a moist cloth that the technician will provide.
  • Begin to urinate into the toilet.
  • While the urine is in midstream, place the specimen cup in the urine stream. Do not allow the cup to touch your genital area.
  • When you have finished urinating, put a lid on the cup and deliver it to the technician.

Urine Drug Test Results

The technician or nurse should be able to inform you of the test results almost immediately.

Immunoassays, the most common type of urine drug screening, do not measure drugs themselves. Rather, they measure how drug use interferes with the body’s ability to form antigen-antibody complexes.

Results of this test are expressed in ng/mL (nanograms per milliliter). The test is based on a cutoff point so that any number below the cutoff is recorded as a negative screen and any number above the cutoff point is interpreted as a positive screen. The people who are responsible for administering the drug test usually provide results in terms of positive or negative as opposed to numeric values.

Many immunoassay tests do not even display the ng/mL measurements. Rather, the results are shown on a test strip that turns different colors to indicate the presence or absence of various substances.

If the results are positive for illegal drugs that you have not taken, you should immediately request a gas chromatography.

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Show Sources

  • Gourlay, D.L., Heit, H.A., Caplan, Y.H. (31 May 2010). Urine drug testing in clinical practice: The art and science of patient care. California Academy of Family Physicians.
  • Moeller, K.E., Lee, K.C., Kissack, J.C. (January 2008). Urine drug screening: Practical guide for clinicians. Mayo Clinic Proceedings, 83(1), 66-76.
  • Standridge, J.B., Adams, S.M., Zotos, A.P. (1 March 2010). Urine drug screening: A valuable office procedure. American Family Physician, 81(5), 635-640.
  • Toxicology screen - MedlinePlus. (n.d.). U.S. National Library of Medicine – National Health Institutes. Retrieved May 29, 2012, from http://www.nlm.nih.gov/medlineplus/ency/article/003578.htm
  • Urine drug screen - MedlinePlus. (n.d.). U.S. National Library of Medicine – National Health Institutes. Retrieved May 29, 2012, from http://www.nlm.nih.gov/medlineplus/ency/article/003364.htm

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