A urine drug test can detect both illegal and prescription drugs in a person’s system. Doctors, sports officials, and many employers require these tests regularly. Urine tests are quick, easy, painless, and cost-effective.

They are a common method of screening for drugs.

Signs of drug use can remain in a person’s system long after the physical effects wear off. The analysis can determine whether a person used specific drugs days or weeks before testing.

In this article, we take a close look at urine drug screens. We describe what they can detect and how long these substances remain traceable in urine.

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Doctors, sports officials, and employers may request these tests.


A doctor may request a urine drug screen if they think that a person has been using illegal drugs or misusing prescription drugs.

For example, a doctor may ask for a urine screen to determine if a person is taking a prescribed opioid medication in a way other than the doctor intended.

A member of an emergency services team may request a urine drug screen if they suspect that a person is behaving strangely or dangerously due to the influence of drugs.

Rehabilitation programs

Drug and alcohol rehabilitation programs may request urine drug screens at initial assessments and follow-up appointments.

Learn more about the treatments for addiction here.

Sporting events

Many sporting officials require urine tests to check whether athletes have used performance-enhancing drugs, such as anabolic steroids.

The World Anti-Doping Agency regulates the use of performance-enhancing substances in many global sports events. Making sure that all athletes are performing without these drugs ensures fair competition.


Some employers request that new staff members take urine drug tests. Or, staff may have to do this on a regular basis.

This is more common in workplaces that require high levels of safety. For example, United States federal law mandates that people working in the transportation industry take regular drug tests.

Laws about employee drug testing differ geographically. A person should check with local authorities.

A urine drug screen can detect a range of drugs, including:

Urine screens can also detect nicotine and cotinine, which the body produces when it breaks down nicotine.

Though a urine test can indicate the presence of alcohol, if a health or legal authority suspects that a person has been drinking in excess, they are more likely to request a breath or blood test.

Learn more about other types of substance tests here.

A doctor or trained technician usually performs a urine drug screening.

There are several types of these tests. An immunoassay (IA) test is most common because it is the quickest and most cost effective.

However, IA tests can give false-positive results. In this case, the results indicate the presence of a drug that the person has not used. False-negative results can also occur.

Another type can confirm the results of an IA test. This is called gas chromatography-mass spectrometry (GC-MS). A GC-MS test is more reliable than an IA test, and it can detect more substances.

Usually, people only request GC-MS tests as follow-ups because they are more expensive, and the results take longer.

Generic IA tests can show cocaine, amphetamines, opioids, cannabinoids, and PCP. A doctor may require a more specialized IA test to check for synthetic and semisynthetic opioids, such as methadone.

It is important to note that consuming certain legal substances can lead to false-positive IA test results. For example, consuming high enough quantities of dextromethorphan, a common ingredient in cough syrups, can cause a positive result for PCP on this type of test.

To minimize the risk of false positives, urine drug screens have cut-off levels. This means that a result is only positive when the test detects an amount of a drug that is above a certain level. Cut-offs also reduce the likelihood of testing positive due to only passive exposure to a drug. Secondhand smoke is one example of passive exposure.

Also, both IA and GC-MS tests can produce false-negative results. These fail to indicate recent drug use. A false-negative result can occur when urine is very diluted, for example.

Many factors can affect when a test can detect a certain drug. Some factors include:

  • the person’s body mass
  • their hydration levels
  • the acidity of their urine
  • how long ago the drug use occurred

Overall, the more frequently and heavily drug use occurs, the longer the drug will be detectable.

Below, for example, we show how long urine tests can detect cannabis.

Frequency of cannabis useDetection times after use
single use2 days
3 times a week2 weeks
daily use2-4 weeks
heavy daily useup to 12 weeks

Other typical drug detection ranges include:

DrugDetection times after use
alcohol7–12 hours
amphetamines2–3 days
short-acting benzodiazepines3–5 days
long-acting benzodiazepinesup to 30 days
buprenorphineup to 11 days
cocaine metabolites2–4 days
codeine1–2 days
fentanyl2–3 days
heroin or morphine1–3 days
methadone3–4 days
oxycodone1–3 days

The test requires little preparation. Usually, a person just has to urinate into a plastic container and return the urine sample to the technician or doctor.

They then measure the temperature of the urine sample to make sure it is suitable for testing. They seal the sample in a plastic bag. If a person cannot return their sample to a medical professional within 1 hour, they should seal it in a plastic bag and store it in a refrigerator.

A technician may accompany the person to make sure that they are giving the sample correctly. The technician should explain the reason for this supervision.

It is important to note that certain medicines and supplements can cause false-positive results.

A person should tell the test provider if they are taking any:

  • prescription medications
  • over-the-counter medicines
  • herbal remedies
  • supplements

Urine drug screen results usually come back within a few days or on the same day.

If a result is positive, a person may need to take a second test for confirmation. This may be a GC-MS test, which gives more accurate results.

The person who carried out the test or a medical review officer will explain the results.

A urine drug screen can quickly, effectively detect some illegal and prescription drugs. Doctors, sports officials, and employers may request this type of test for various reasons.

The screening can detect a range of substances, including cannabis, nicotine, barbiturates, and opioids such as heroin and methadone. Some remain traceable in the body longer than others.

If an initial result is positive, a person may need to take a second, more accurate test.