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Drug Testing Test

A drug test looks for signs of illegal drugs or certain prescription and over-the-counter medicines that can be misused. It can also check for alcohol use. The test is usually done with a urine sample, but may use blood, saliva, hair, sweat, fingernails, or breath.

What this test measures

The test measures the presence of drugs or their byproducts in your body. It can detect illegal drugs (like cocaine, heroin, marijuana, amphetamines), misused prescription medicines (like opioids, barbiturates, benzodiazepines), and misused over-the-counter medicines (like dextromethorphan).

What your results mean

Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.

Higher-than-normal 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.

Lower-than-normal results

If a drug test result is negative, it means that either the drugs tested were not found in your sample, or a very small amount was found but not enough to count as a positive result.

Frequently asked questions

What does a drug test look for?

It looks for signs of illegal drugs, misused prescription medicines, and misused over-the-counter medicines. It can also check for alcohol use.

How is a drug test usually done?

The test is usually done with a sample of your urine. Less commonly, it uses blood, saliva, hair, sweat, fingernails, or breath.

Can a drug test tell if I have an addiction?

No, a drug test can't diagnose a drug use disorder (addiction). It only shows whether you have used or misused drugs.

What happens if I get a positive result?

You'll usually have a follow-up urine test called a confirmatory test to make sure the first test was correct. This is because the first test can sometimes give false positives.

What can cause a false positive result?

False positives can happen if the test reacts with other chemicals in your body from certain over-the-counter medicines, prescriptions, and foods.

Related lab tests

Sources

Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.