What is a Drug Test?
A drug test looks for signs of one or more illegal or prescription drugs in a sample of your urine (pee), blood, saliva (spit), hair, or sweat. The purpose of a drug test is to look for drug use and misuse, which includes:
Using any illegal drugs, such as cocaine or club drugs
Misusing prescription medicines, which means taking prescription medicines in a different way or for a different purpose than your provider prescribed. Examples of drug misuse include using a prescription pain reliever to relax or taking someone else's prescription.
A drug test can check for a single drug or for a group of drugs in your body. Drug tests commonly test for: alcohol，amphetamines, including methamphetamine，barbiturates, such as phenobarbital and secobarbital，benzodiazepines, such as alprazolam or clonazepam，cocaine，marijuana (THC)，opioids and opiates, such as heroin, codeine, oxycodone, morphine, hydrocodone, and fentanyl，Phencyclidine (PCP)，Steroids.
Most drug tests use urine samples. These tests can find signs of drugs within hours to several days or more before the test. How long a drug lasts in your body depends on:
- The type of drug
- How much you used
- How long you were using it before the test
- How your body reacts to the drug
Other names: drug screen, drug test, drugs of abuse testing, substance abuse testing, toxicology screen, tox screen, sports doping tests
What is it used for?
Drug testing is used to find out whether you have been using or misusing one or more drugs. But it can't diagnose a drug use disorder (addiction).
A drug test may be used for different purposes, including:
- Employment. Employers may screen you for drugs before hiring you. After you're hired, they may test you to check for on-the-job drug use. If you have a work accident, you may be tested to see whether drugs or alcohol were involved.
- Sports. Professional and other athletes are often tested for drugs that are used to improve performance, such as steroids that help build muscle.
- Drug treatment. Drug testing may be used to monitor treatment in programs for drug or alcohol use disorder.
- Legal evidence. Testing may be part of a criminal or motor vehicle accident investigation. Drug screening may also be ordered as part of a court case.
- Monitoring misuse of prescription drugs. If your provider prescribed a medicine that can be addictive, such as an opioid for long-term pain, your provider may order a drug test to make sure you're taking the medicine correctly.
Drug testing may be scheduled ahead of time or done randomly without notice.
Why do I need a drug test?
You may be asked to take a drug test for a job, to participate in certain organized sports, or as part of a police investigation or court case. In a hospital emergency room, a provider may order a drug test if you have signs of a possible drug overdose.
Are there any risks to the test?
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.
Before you take a drug test, make sure you know:
- What you are being tested for
- Why you are being tested
- How the results will be used.
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 do the results mean?
If a drug test result is negative, it means that either:
- The drugs that were tested were not found in the sample.
- A very small amount of drugs were found, but not enough to be a positive test result for drugs.
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 tests require follow-up testing because they may be wrong (false positives). The follow-up test is usually a test that provides more accurate results.
Learn more about laboratory tests, reference ranges, and understanding results.
Is there anything else I need to know about a drug test?
- At-home tests let you do the entire test at home and get rapid results. But if the test result is positive for drugs, you'll need to have a follow-up lab test to check the accuracy of the result. Some at-home tests include a kit for collecting a sample, often urine or saliva, to send to a lab in case the home test is positive. When using home tests, be careful to follow all the instructions. It's best to talk with your provider about using home drug testing so you can decide if it's right for your situation.