How to Find and Use Fentanyl Test Strips

Medically Reviewed by Carol DerSarkissian, MD on May 27, 2024
4 min read

Fentanyl is a synthetic opioid that’s 50-100 times stronger than the pain reliever morphine. While some people use fentanyl on purpose, many others get it in their systems without their knowledge. That’s because drug dealers often mix fentanyl -- which is inexpensive but strong -- into other drugs like heroin, cocaine, methamphetamine, and MDMA.

If you take fentanyl without knowing it, you might get a much higher dose of opioids than your body can handle, putting you at risk for an overdose. Fentanyl test strips can help. They detect the presence of fentanyl in drugs you intend to use.

Of course, the safest option is not to use illegal drugs at all or to seek out a drug addiction treatment program if you need help stopping. But if you’re going to use street drugs, testing them for fentanyl first might save your life.

Fentanyl test strips are small strips of paper that were originally created to detect fentanyl in urine. But you can also use them to see whether a drug contains fentanyl in just a few minutes.

Each strip costs about a dollar. But you might be able to get strips for free from your local health department, a needle exchange program, or other community-based organization. You can also buy them online at sites including,, and even

Fentanyl test strips aren’t legal everywhere because some states consider them to be drug paraphernalia (items you need to do drugs). But a growing number of health and public policy experts are supporting their use along with other harm-reduction strategies.

In 2021, the CDC and the Substance Abuse and Mental Health Services Administration (SAMHSA) announced that federal grant recipients, such as nonprofit drug-treatment and harm-reduction centers, can use grant money to buy the test strips.

Fentanyl test strips are easy to use, and they work well. Most are at least 96% accurate in detecting fentanyl as well as many fentanyl analogs (drugs that are chemically similar but not identical to fentanyl).

When you use an illegal drug, there’s no guarantee that it contains what the dealer or person who gave it to you says it does. What’s more, you can’t see, taste, or smell fentanyl. The only way to know if a drug has been contaminated with it is to test it. There are a few ways to test for fentanyl in a drug sample, but the easiest (and only do-it-yourself) option is to use a test strip.

Research has shown that people who use fentanyl test strips often make changes that can keep them safer. In one study from the Johns Hopkins Bloomberg School of Public Health, 70% of participants said they would change their behavior if they knew the drugs they used contained fentanyl.

Other research from Brown University showed that half of test strip users found fentanyl in their drug supply. Of those who detected fentanyl, more than 40% decided to use a smaller amount of the drugs or to go more slowly to reduce their risk of overdosing. A similar percentage chose to use their drugs with other people (instead of alone) so someone would be around to call 911 or give them naloxone (Narcan), if needed, to reverse an opioid overdose.

Fentanyl test strips aren’t perfect, but most people find them easy to use. The best way to use them is to dissolve all the drugs you plan to use in water. Fentanyl might not be everywhere evenly in your product, so if you only test a portion of your supply you might end up missing it.

Use 1 teaspoon of water per every 10 mg of crystal or powder meth, MDMA, or ecstasy to dissolve the drugs in a small container (like a soda bottle cap). If you’re using a different type of drug, use half a teaspoon of water instead.

If you’re using pills, you’ll need to crush a pill on a clean surface before dissolving it in 1 tablespoon of water. If you plan to use IV drugs, prepare the shot, set the needle aside, and add about one-fifth teaspoon of water to the spoon/cooker with the drug.

If you decide to use the drugs after testing them, you can drink them or inject them. Or you can get the powder back by letting the water evaporate. You can speed up the process by putting the dissolved drugs in a pan in the oven on the lowest setting (maximum of 225 F) while keeping the oven door cracked. When the water evaporates and the pan is cool, you can scrape the residue off with a razor or other sharp item.