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Fentanyl test strips: where to get & how to use?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Aug 15, 2022.

Official answer


Key Points

  • Fentanyl test strips can be found at your local health department, at a needle-exchange program (that distributes clean syringes) in your community, from reliable online sources, or even vending machines in some states, like Ohio.
  • The BTNX Rapid Response Fentanyl Test Strips are a common brand found in the U.S. and in other countries. Once the BTNX strip is dipped into a sample of the drug dissolved in water, the results indicate if fentanyl is present. One line usually means the sample is positive for fentanyl, two lines usually means it is negative, and no lines or no control line means it's invalid. Follow the exact instructions found in your test strip package.
  • The strips typically cost about $1 or $2 per strip, or they may be free from your local health department.
  • If you choose to use illegal drugs, always have a plan and don't use alone.

How do I use fentanyl test strips?

If your strips come with specific directions, follow those directions exactly.

The general directions for BTNX fentanyl test strips are:

  • Dissolve a small amount of drug into a small amount of water and dip the test strip into the water for 15 seconds. The test strips are highly sensitive.
  • Lay the strip on a flat surface for 5 minutes. Results should appear within this time frame.
  • If one line appears, the result is typically positive and fentanyl has been found in the drug sample. If two lines appear, the result is usually negative. If no lines appear, or no control line appears, the test in invalid. It should be repeated with a new test strip. Do not reuse the test strip.
  • Remember that no test is 100% accurate and your drug may still contain fentanyl or an analog.

Even if your drugs test negative for fentanyl, use caution and follow the harm reduction steps (see below) if you are using drugs for recreational purposes.

What are fentanyl test strips?

Fentanyl test strips are an important tool to help prevent a drug overdose from illegally-made fentanyl, a potent and often deadly opioid. Fentanyl test strips can be used to determine if drugs have been mixed or cut with fentanyl. They can be used to sample street drugs like heroin, methamphetamine, cocaine, and illegally obtained prescription pills. The strips give those who use illegal drugs a way to determine if fentanyl is present in their drug supply and to help reduce the risk of an overdose.

Legal fentanyl is a synthetic prescription opioid developed in the 1960s and is used to treat severe pain such as breakthrough cancer pain in patients who are opioid-tolerant.

  • It is 50 times stronger than heroin and 100 times stronger than morphine.
  • Legal prescription products are available in a variety of dosage forms, including skin patches, oral lozenges, oral buccal tablets (placed in cheek/gum area), nasal spray, sublingual spray (sprayed under the tongue) and as an injection.
  • In the U.S. they are schedule II controlled substances and only prescribed by a healthcare provider.

Illegally manufactured fentanyl is fueling the increase in drug overdoses in the U.S. It is often contained in illicit drugs without the user’s knowledge. It may be laced into other illegal street drugs, such as cocaine, heroin, fake opioid pills, or methamphetamine (“meth”). It is relatively cheap to make and allows an illicit drug manufacturer to stretch their product, make it more powerful and addictive, and gain more money for themselves.

The risk is especially high among persons who are not tolerant to the drugs effects (opioid-naïve) and may not be aware that the drugs they use contain fentanyl. Because fentanyl is so potent, its use in people who are naïve to fentanyl use can quickly lead to overdose and death.

What do fentanyl test strip studies say?

Studies have shown that fentanyl test strips can increase awareness and lead to safety precautions to help prevent an overdose.

  • In North Carolina, a community-based fentanyl test strip distribution program found that 81% of those with access to the strips when on to test before illicit drug use. When a positive result was seen, people were 5 times more likely to change their drug use behavior to lower their overdose risk.
  • A Rhode Island study found that younger adults using heroin, cocaine, or illegally obtained prescription pills who obtained a positive fentanyl test on their drugs led to a significant change in overdose risk behavior.
  • A study from Brown University Medical Center and Johns Hopkins University found the test strips were accurate in detecting fentanyl and unlikely to produce false negative results.

There are a few drawbacks to fentanyl test strips. False positives may occur, the strips do not tell you how much fentanyl is present or how potent it is, and not all states consider the strips legal.

The test strips are also surrounded by controversy: some worry these tests create a false sense of security or justify the use of illegal drugs. It also assumes the user is acting rationally and will avoid use of a drug if it is detected, but this may not always be the case. However, fentanyl tests strips should be considered an important tool in opioid harm reduction.

Are fentanyl test strips legal?

Not in all U.S. states. Based on previous legislation in some states, fentanyl test strips are classified as drug paraphernalia and are considered illegal.

  • A recent 2022 study in Drug and Alcohol Dependence found that in 22 states it is legal to possess the tests, in 19 states it is legal to distribute them to adults, and in 14 states it is legal to have them when that equipment is obtained from a syringe services program.
  • A growing number of states have decriminalized or legalized their possession and use, and many states do not prosecute those found with the strips.
  • However, there is a large disparity in laws surrounding fentanyl test strips in the U.S. Penalties for possession of test strips can range from small fines to multi-year jail sentences.

Where to buy fentanyl test strips?

Some online retailers sell fentanyl test strips, and certain states such as Ohio are now providing test strips in vending machines for easier access, sometimes along with naloxone. When buying online, use extreme caution to be sure the tests are valid.

Contact the syringe services program or Dept. of Health and Human Services in your state. These groups may be able to provide test strips free of charge, or know where you can get them.

How can I protect myself from a drug overdose?

  • Do not use drugs alone
  • Use fentanyl tests strips
  • Find and utilize a local clean needle-exchange program.
  • Carry naloxone (Narcan) and encourage friends and family to have access, as well. Learn how to use it before an emergency situation occurs.
  • Avoid mixing drugs.
  • Be sure every time you use you have a plan with others in case of an overdose.
  • Speak to a healthcare provider about opioid use disorder treatment with buprenorphine or methadone.

For more information, you can contact find evidence-based treatment and service options near you by visiting or by calling the 24/7, National Helpline at 800-662-HELP (4357).

This is not all the information you need to know about fentanyl test strips for safe and effective use and does not take the place of your healthcare provider's advice. Review and follow the full test strip information before use, as directions may vary among tests. Discuss this information and any questions you have with your doctor or other health care provider.


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