Drug Testing
Reviewed
Also called: Drug Screen, Drugs of Abuse Testing, Substance Abuse Testing, Toxicology Screen, Tox Screen, Sports Doping Tests
A drug test looks for signs of illegal drugs or certain prescription and/or over-the-counter (OTC) medicines that can be misused.
Specimen: Urine (most common), blood, saliva, hair, sweat, fingernails, or breath
Why this test may be ordered
- Employment screening (pre-employment or on-the-job)
- Sports doping testing for performance-enhancing drugs
- Monitoring treatment for drug or alcohol use disorder
- Legal evidence (criminal or motor vehicle accident investigation)
- To prevent prescription drug misuse (e.g., opioids for chronic pain)
Preparation and collection
Be sure to tell the testing professional if you are taking any prescription drugs, over-the-counter medicines, or supplements, because these substances may affect your test results. Also, you should avoid foods with poppy seeds, which can show up as opiates in a drug test.
Urine is the most commonly used sample for drug testing. You will be given instructions for how to collect your sample. In certain cases, a health care professional or other person may need to be present while you provide your sample. This is to make sure the urine is yours and isn't contaminated with anything that might affect the test results.
There are no known physical risks to having a drug test. But if drugs show up in your results, it may affect your job, your eligibility to play sports, the outcome of a legal matter, or other parts of your life.
Understanding results
If a drug test result is positive, it means that one or more drugs were found in amounts that suggest drug use or misuse.
- Positive: If a drug test result is positive, it means that one or more drugs were found in amounts that suggest drug use or misuse. Limitation: That's because the type of urine testing that's often done first can have false positive results. False positives can happen if the test reacts with other chemicals in your body from certain over-the-counter medicines, prescriptions, and foods. Next step: If you have a positive test result, you'll usually have a follow-up urine test to make sure the first test was correct.
- Negative: If a drug test result is negative, it means that either: The drugs that were tested were not found in your sample, A very small amount of drugs was found, but not enough to count as a positive test result for drugs. Limitation: Drug tests can find signs of drugs that you took hours to several days or more before the test. Next step: If you have questions or concerns about a drug test, talk with your provider or the person or organization that is asking for the test.
- A positive result may affect your job, sports eligibility, legal matters, or other aspects of your life.
- False positives can occur due to certain over-the-counter medicines, prescriptions, and foods (e.g., poppy seeds).
- A confirmatory test is needed after a positive initial test to verify accuracy.
- This test cannot diagnose a drug use disorder (addiction).
What to do next
If you have questions or concerns about a drug test, talk with your provider or the person or organization that is asking for the test.
- What am I being tested for?
- Why am I being tested?
- How will the results be used?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.