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Fentanyl Test Strips

Fentanyl-laced drugs can be deadly. Learn how to use fentanyl test strips and where to get them.

Taking illegally manufactured fentanyl is unsafe and can cause a fatal overdose. But it is very difficult to know whether illicit drugs contain fentanyl. Virtually any type of recreational drug obtained from a nonmedical source may be laced with fentanyl. Fentanyl has been found in heroin, cocaine, MDMA (aka ecstasy or molly), ketamine, methamphetamine, cannabis, and counterfeit prescription painkillers. In fact, the majority of overdose deaths now involve synthetic opioids, primarily fentanyl.

Fentanyl test strips help you rapidly detect fentanyl and other synthetic opioids in a batch of drugs. Using the strips can reduce your risk of taking tainted, and potentially life-threatening, substances.

If you or a loved one uses illicit drugs, take steps to prevent a fentanyl overdose. Carry, use, and share fentanyl test strips, which can save lives.

Carry naloxone, an over-the-counter nasal spray that can reverse an opioid overdose.

If you suspect someone is experiencing an opioid overdose, call 911 and administer naloxone if it’s available. Keep the person awake and lying on their side until first responders arrive. Learn more.

Why test drugs for fentanyl?

Black-market drug suppliers increasingly mix illicit drugs, including counterfeit prescription opioids, with the synthetic opioid fentanyl. Suppliers do this because mixing drugs with fentanyl makes them cheaper and more addictive.

However, lacing drugs with fentanyl makes them far more likely to cause accidental overdoses, which can be lethal. According to the Centers for Disease Control and Prevention, taking even the smallest amount of fentanyl — an amount equal to three grains of salt — can be harmful or deadly. In 2021, about 66% of the estimated 107,622 drug overdose deaths in the United States were linked to synthetic opioids such as fentanyl.

Without testing, it’s nearly impossible to tell whether drugs are free of fentanyl. Fentanyl can’t be seen, tasted, or smelled. Fentanyl test strips are a simple, low-cost tool used to rapidly check for fentanyl in a batch of drugs — including in tablets, powders, and injectable liquids.

What are other ways to prevent a fentanyl or other opioid overdose?

Fentanyl test strips are one tool for preventing an opioid overdose. Consider taking these additional steps for safety:

  • Carry naloxone (sold under the brand named Narcan), an overdose-reversal medication.
  • Don’t use any opioid, including fentanyl, by yourself. If you are using opioids, always have a “drug chaperone” with you. This should be someone who is not using drugs at the time and who has naloxone and knows how to use it.
  • Don’t mix opioids with alcohol or other drugs, which can make them more dangerous. 
  • Test every batch of illegal drugs for fentanyl. Don’t trust even your regular supplier, since they might not know what’s in their drug supply. 

Recovery from opioid dependence is possible. Find a treatment provider near you.

How do you use fentanyl test strips?

Not all fentanyl test kits are exactly alike, so always read and follow the manufacturer’s instructions. 

The general steps for most test kits are as follows:

  • Dissolve some or all of the drugs in water.
  • Dip the fentanyl test strip into the water-drug solution.
  • Wait as long as specified (usually about 15 seconds) for the test strip to absorb the solution.
  • Remove and place the test strip on a flat surface and wait for the time indicated — usually just a few minutes.
  • Read the results of the test.  

How much do you need to test? 

If your drugs are laced with fentanyl, the fentanyl may not be distributed evenly throughout the supply. That’s why experts recommend testing the entire drug supply. The test strips can also be used to test very small samples or even the residue of the supply. 

Most tests kits require you to test at least 10 milligrams. Some tests come with a milligram scale or a 10-milligram scoop and require different dilution processes. 

The ratio of drugs to water may differ depending on the substance or type of test kit. As a general rule, experts recommend:  

  • Testing methamphetamine, MDMA, or ecstasy by dissolving 10 milligrams of the drug in 1 teaspoon of water. 
  • Testing other drugs by dissolving 10 milligrams in half a teaspoon of water. 

Remember, fentanyl test strips are not all the same. Use the test kit exactly as directed. 

How do you read the test results? 

Most fentanyl test strips provide rapid results in the following ways: 

  • Positive (one red line). YES, fentanyl or a similar synthetic opioid is present.
  • Negative (two red lines). NO, fentanyl or a similar synthetic opioid was not detected.
  • Invalid (no lines appear, lines are faded, or a single line appears in the wrong place). Perform the test again.

Graphic providing instructions to read a fentanyl test strip

Fentanyl test strips can tell you whether fentanyl is present in a drug supply but not the amount or strength of the fentanyl present.  And if you test only a portion of the drugs, you can miss fentanyl in other parts of the supply. 

How accurate are fentanyl test strip results?

Fentanyl strips are a reliable way to rapidly detect the presence of fentanyl in illicit drugs. By one estimate, they are 92%–96% effective in detecting fentanyl.  The most common reason that fentanyl test strips fail is user error, so be sure to closely follow the test kit instructions.

Because fentanyl tests are not 100% accurate, a negative result does not guarantee that your drug sample is free from all synthetic opioids or other harmful substances. Fentanyl test strips can’t detect certain other synthetic opioids, such as isotonitazene. 

In addition, it is possible for one portion of a drug to contain fentanyl while another does not. This is known as the “chocolate chip cookie effect.”

For these reasons, the surest way to avoid an overdose is to not take illicit drugs.

Fentanyl test kits can help you determine whether illicit drugs contain fentanyl. 

But even illicit drugs that are tested should not be considered “safe.” Consuming almost any drug — especially one sold illegally — carries some inherent risk.

Recovery from a substance use disorder is possible. Learn how to create a recovery plan.

Where can you get fentanyl test strips?

Here’s what to know about getting fentanyl test strips:

State laws are evolving. Many states once categorized fentanyl test strips as illegal drug paraphernalia. Now, more than half of U.S. states have passed laws allowing people to buy and use fentanyl test strips. Check your local laws to see if there are any restrictions in your area. 

There may be free or low-cost distribution programs in your area. Look for public health agencies or organizations in your area that offer free or low-cost fentanyl test strips. These may include harm reduction organizations, opioid overdose prevention programs, or needle exchanges.

You can order fentanyl test strips online. You can buy fentanyl test strips for $1–$2 per single-use strip. Retailers and nonprofit organizations that sell and ship fentanyl test strips include Amazon, BTNX, Bunk Police, DanceSafe, Dosetest, North American Syringe Exchange Network (NASEN) Buyers Club, and Walmart. 

Some nonprofit organizations provide fentanyl test strips for free by online mail order. Examples include BirdieLight and NEXT Distro.

Recovery is possible. Find options for treatment and recovery.

This resource was produced collaboratively with a group of Education Development Center (EDC) subject matter experts who reviewed the content and provided their insights. Last reviewed May 2023.

Content reviewed by Jasleen Salwan, MD, MPH, FASAM, August 2023. 


CDC Launches New Education Campaigns Aimed at Preventing Drug Overdose Deaths, Centers for Disease Control and Prevention, Oct. 27, 2021

Department of Justice Announces Results of Enforcement Surge To Reduce the Fentanyl Supply Across the United States, U.S. Department of Justice, Sept. 27, 2022

Drug Overdose Death Rates, National Institute on Drug Abuse, June 30, 2023

Fentanyl Facts, Centers for Disease Control and Prevention, Feb. 23, 2022

Fentanyl Test Strips, Legislative Analysis and Public Policy Association, May 2021

Fentanyl Test Strips: A Harm Reduction Strategy, Centers for Disease Control and Prevention, Sept. 30, 2022

Fentanyl Test Strips Prove Useful in Preventing Overdoses, Brown University, Oct. 18, 2018

Fentanyl Test Strips To Prevent Drug Overdose, Minnesota Department of Health

Five Fentanyl Test Strips, BirdieLight

Harm Reduction Issues: Fentanyl, National Harm Reduction Coalition

How To Test Your Drugs Using Fentanyl Test Strips, New York City Health Department

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New Fentanyl Test Strips – Single Strip, DanceSafe

Overdose Deaths Reached Record High as the Pandemic Spread, The New York Times, Nov. 17, 2021

Overdose Reversal Drugs Gain Support at Music Festivals, but Not Fentanyl Test Strips, NPR, Aug. 3, 2022

Trends and Geographic Patterns in Drug and Synthetic Opioid Overdose Deaths — United States, 2013–2019, Centers for Disease Control and Prevention, February 12, 2021

U.S. Overdose Deaths in 2021 Increased Half as Much as in 2020 – But Are Still Up 15%, Centers for Disease Control and Prevention, May 11, 2022