Urine Drug Test

Medically reviewed by Judith Marcin, MD on July 3, 2017Written by Debra Stang

Understanding the urine drug test

A urine drug test, also known as a urine drug screen or a UDS, is a painless test. It analyzes your urine for the presence of certain illegal drugs and prescription medications. The urine drug test usually screens for:

Alcohol can also be included in screening tests, but it’s usually detected through breath tests rather than urine screens.

A urine drug test can help a doctor detect potential substance abuse problems. After a drug test identifies drugs you may be misusing, doctors can help you start a treatment plan. Taking urine drug tests throughout substance abuse treatment helps to ensure that the plan is working and that you’re no longer taking drugs.

Purpose of the urine drug test

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

For example, your primary care doctor may order this test if they suspect you have a problem with drugs or alcohol. An emergency room doctor may also request this test if you’re confused or your behavior seems strange or dangerous.

Learn more: Illicit drug addiction »

Many employers require potential employees to take a urine drug test before they can be hired. One benefit of the urine drug screen is that it can keep people with drug problems out of jobs that require the ability to be alert and focused. For instance, an air traffic controller or truck driver who uses drugs could put the safety of many people at risk. Testing may also lower the risk of on-the-job accidents.

Drug and alcohol rehabilitation centers test residents on a regular basis. This helps ensure that people receiving treatment for drug or alcohol abuse stay sober. If you’re 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 your sobriety.

Finally, the tests can be used in home settings. For instance, a family member may want a loved one to take this test to prove that they’re not using drugs or alcohol. If you plan to use an at-home test, it’s a good idea to consult with your family doctor or another health professional beforehand. They 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 fairly quickly. However, it has drawbacks. For example, it doesn’t pick up on all opioids. Also, it sometimes gives false positives. A false positive occurs when the test results come back positive for drugs, but there has been no drug use.

Read more: Opioid abuse and addiction »

If your first test comes back positive, a follow-up test known as gas chromatography/mass spectrometry (GC/MS) is done for confirmation. This type of test uses the same procedure for getting a urine specimen as the immunoassay. GC/MS results are more expensive and take longer to give results, but they rarely produce false positives.

Both types of tests can create a false negative, which is when the test reports a negative result even if there is drug use. Both tests can also fail to capture same-day drug use.

How to take the test

You will likely take the urine drug test in a bathroom specifically prepared for drug testing. The test procedure includes the following steps:

  1. You will receive a specimen cup from the person administering the test.
  2. You’ll need to leave your purse, briefcase, or other belongings in another room while you take the test. You’ll also need to empty your pockets.
  3. In rare cases, a same-gendered nurse or technician will accompany you into the bathroom to make sure you follow all testing procedures. They should explain the reason for this type of supervised testing.
  4. Clean your genital area with a moist cloth that the technician provides.
  5. Urinate into the cup. You need to produce at least 45 milliliters for the sample.
  6. When you finish urinating, put a lid on the cup and bring it to the technician.
  7. The temperature of your sample will be measured to ensure that it’s in the expected range.
  8. Both you and the collector must keep visual contact with the urine specimen at all times until it’s been sealed and packaged for testing.

Urine drug test results

Some sites have instant results, some do not. Depending of the reason for the drug test, the sample is often sent out for testing so that a formal report can be generated.

Immunoassays, the most common type of urine drug screening, don’t measure drugs themselves. Rather, they detect how the drug interacts with the body’s immune system and its ability to form antigen-antibody complexes.

Results of this test are expressed in nanograms per milliliter (ng/mL). The test uses a cutoff point. Any result below the cutoff number is a negative screen and any number above the cutoff number is a positive screen.

If it’s an instant result, the people who administer the drug test usually give the results in terms of positive or negative rather than numeric values. Many instant immunoassay tests don’t display the ng/mL measurements. Rather, the results appear on a test strip that turns different colors to indicate the presence of various substances.

If you get a positive result for illegal drugs that you haven’t taken, you should make sure to get a GC/MS follow-up test immediately. You will also want to talk to the medical review officer (MRO). This is the physician in charge of interpreting and reporting the results of any drug testing done in their facility.

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