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Fentanyl Test Strips: Preventing an Overdose

Fentanyl is a potent synthetic opioid that is commonly used as a cutting agent in illicit street drugs like heroin, cocaine, methamphetamine, and MDMA. In 2019, 93% of the fatal overdoses in Massachusetts involved fentanyl.1 In response to these alarming numbers, the commonwealth has focused its efforts on harm reduction strategies, such as distributing fentanyl test strips (FTS) to help people who use drugs prevent an overdose.

The only way to be sure that your drugs do not contain fentanyl is to test them. If you test your drugs for fentanyl and they are positive, discard of them immediately to prevent an overdose.

What Are Fentanyl Test Strips?

Fentanyl test strips (FTS) are thin paper strips that can detect tiny amounts of fentanyl. Using a similar method as at-home pregnancy tests, they are affordable and easy to use.

While FTS were originally designed to test urine, they can also be used to test powders.1 Testing products before you use them can help you make better decisions about if and how you use drugs to prevent an overdose.

Drug checking with fentanyl test strips is simple. You can test for fentanyl in your product by diluting a small amount of the drug in water and then using a test strip to determine if fentanyl is present.

BTNX is a Canadian biotech company that manufactures most of the FTS on the market. Using their Rapid Response Fentanyl Forensic Test Kit, you can detect fentanyl as well as other fentanyl analogues like:2

  • Carfentanil
  • Remifentanil
  • Butyryl Fentanyl
  • Sufentanil
  • p-Fluoro Fentanyl
  • Furanyl Fentanyl
  • Acetyl Fentanyl
  • Valeryl Fentanyl
  • 3-Methyl Fentanyl, and Ocfentanil.

Fentanyl test strips have a high sensitivity and a low detection limit, making them one of the most accurate and effective drug checking methods available.

Preventing Overdose

Because street drugs are frequently laced or cut with other less expensive drugs like fentanyl, people may be unaware of the hidden dangers contained within the drugs they use.

The only way to prevent an overdose is to know what’s in the drug you plan to take. The more informed you are about the drugs you use, the smarter choices you can make regarding if, when, and how much you use.

While some have argued that the use of test strips won’t change the way people use drugs, research proves otherwise.

One study conducted in 2018 showed that people who use drugs did in fact change their behavior. When they were informed about the presence of fentanyl in their drugs, 56% took precautions to reduce the risk of overdose.3 And even when the fentanyl test strips showed a negative result, 22% took precautions to prevent overdose anyway. Another study in 2019 confirmed that FTS can be an effective harm reduction strategy.4

Checking your drugs before you use them can save your life.

Where to Find Fentanyl Test Strips in Massachusetts

You can purchase fentanyl test strips from online retailers for around $1 each, but if you can’t afford to buy them, other options are available.

Fentanyl test strips have not always been widely available due to laws that prohibit the possession of drug paraphernalia, but authorization was granted in April 2021 to allow community organizations to use federal funding to purchase FTS.5

As a result, FTS can now be obtained from many local harm reduction organizations and syringe exchange programs.

If you live in Massachusetts, contact your local public health agency to inquire about the availability of FTS. Supplies are often limited due to funding constraints, so it’s best to contact the organization directly.

Here are a few Boston area organizations that may offer free FTS:

  • AHOPE (Boston Public Health Commission): 774 Albany Street, Boston, MA 02118, (617) 534-3976
  • Access Drug User Health Program: 359 Green Street, Cambridge, MA 02139, (617) 470-0994
  • Healthy Streets: 100 Willow Street, Lynn, MA 01901, (339) 440-5633
  • ONESTOP Harm Reduction Center: 9 Center Street, Gloucester, MA 01930, (978) 381-3170
  • Never Use Alone: (800) 484-3731

You can also purchase FTS directly from these online retailers:

  • BTNX: 1-888-339-9964
  • Dose Test: 427 E 17th St Ste F, Costa Mesa, CA 92627
  • Dance Safe: (888) 636-2411, 12081 W Alameda Pkwy #442, Lakewood, CO, 80228
  • Amazon

How to Use a Fentanyl Test Strip to Test Your Drugs

Once you’ve obtained a supply of FTS, it’s important to understand how to use them properly.

Here’s how to use a fentanyl test strip to test your drugs:6

  • Step 1: Prepare your drugs
    • Option 1: Dissolve the drugs you plan to use in water following the instructions in step 2. (This is the most accurate method.) You can still use your drugs after you test them.
    • Option 2: If you use pills, finely crush the pills on a clean surface before testing. In pill form, fentanyl does something called “chocolate chipping,” which means it can clump up rather than being evenly dispersed. That means if you only test a small portion of your pill, fentanyl may not be detected. Crushing them and mixing them thoroughly before testing will give you a more accurate reading. Next, place the crushed drugs in a small plastic bag and shake the bag to mix them. Then, empty your drugs from the bag and set them aside. A small amount of drug residue should be left in the bag. Add water to the bag and follow the instructions in Step 2.
    • Option 3: Place 10 milligrams (mg) of your drugs (enough to cover Abraham Lincoln’s hair on a penny) in a clean, dry container. Add water to the container by following the instructions in Step 2.
  • Step 2: Add water
    • Add water to your drugs and mix them thoroughly. For meth, MDMA, and ecstasy, use 1 teaspoon of water for every 10 mg of crystal or powder you are testing. For all other drugs, use a half teaspoon of water.
  • Step 3: Use a test strip
    • Place the test strip (wavy side down) in the water solution and let the strip absorb the water for 15 seconds. Next, take the strip out of the water and place it on a flat surface for two minutes. Then, read the results.

Note: Do NOT use the same test strip more than once.

What to Do If the Test is Positive

After testing, your fentanyl test strip will show one of three results:

  • Positive (fentanyl is present)
  • Negative (fentanyl is not present)
  • Invalid (The test is inconclusive)

If the test is positive, it means that a synthetic opioid was detected in your drugs. At that point, you may choose not to use the drug to prevent your risk of overdose. If so, be sure to safely discard your drugs at a local drop box location to prevent harm to family members and pets.7 If you do not have a drop box in your area, check the U.S. Food & Drug Administration (FDA) Flush List to see which drugs can be flushed safely down the toilet.8

If you still plan to use the product despite the presence of fentanyl, there are some steps you can take to reduce your risk of overdose.

The Drug Overdose Prevention and Education (DOPE) Project, a program supported by the National Harm Reduction Coalition, offers the following suggestions to help reduce your risks of overdose:9

  • Use slow: Take your drugs slowly.
  • Use less: Use less of the drug than you originally planned.
  • Avoid injections: Smoke or snort your drugs instead of injecting them.
  • Space doses: Space your doses further apart.
  • Carry naloxone: Always keep naloxone (Narcan) nearby when you are using drugs.
  • Don’t use alone: Make sure someone else is present when you are using drugs. If you don’t have someone to help, call the Never Use Alone Hotline at 800-484-3731.

If the test is invalid, use a new strip and test the product again.

It’s important to understand that fentanyl test strips can produce false negatives.4 This means it is possible for a test strip to indicate that Fentanyl is not present when it actually is. One study found the incidence of false negatives to be small—around 3.7%.10 Regardless, the number is significant enough to recognize that fentanyl test strips are not 100% accurate. Similarly, while an FTS may tell you if fentanyl is in the product, it doesn’t tell you how much.11

Remember: You can always reduce your dose if you discover that fentanyl is present, but you can’t take it out of your body after you’ve delivered a dose. If you are using your drugs with someone else and you suspect they have overdosed, call 911 immediately. The Massachusetts Good Samaritan Law protects you from prosecution if seek emergency medical attention for an overdose.

Find a Rehab for Drug Addiction

Another great way to prevent a drug overdose is to attend rehab. At an addiction treatment program, you can learn coping strategies, impulse control skills, stress management, and relapse prevention strategies to help you obtain and maintain sobriety in the long run. Individual therapy will help you address the underlying issues that caused you to misuse drugs in the first place, while group counseling will help you learn from others and improve your sober social skills.

If you’re ready to make a positive change in your life, consider seeking a drug addiction treatment program in Boston or elsewhere. Call our confidential helpline at (857) 577-8193 to speak to a knowledgeable treatment support specialist. We will help you find a rehab program that’s right for you and your situation.

Frequently Asked Questions About Fentanyl Test Strips

How Potent is Fentanyl?

According to the Center for Disease Control and Prevention (CDC), fentanyl is 50 times stronger than heroin and 100 times stronger than morphine.12 At this potency, the amount of fentanyl equal to just a few grains of salt can be fatal.13

Can You Tell if Something Has Fentanyl in It?

Because fentanyl is a whiteish powder that resembles many other drugs, it is impossible to tell if a substance contains fentanyl based on color or appearance alone.  The only way to know for sure if a substance contains fentanyl is to test it.

Can Fentanyl Test Strips Be Stored in the Freezer?

Fentanyl test strips should be stored between 2-30°C (36-86°F).2 Storing fentanyl test strips in the freezer could lead to inaccurate readings.

Can You Buy Fentanyl Test Strips at the Pharmacy?

Because drug paraphernalia laws in some areas prohibit the use of FTS, few pharmacies carry the strips. As legislation continues to evolve, life-saving harm reduction strategies like FTS are becoming more common throughout the country. To find out if FTS are available in your local pharmacy, contact them directly to inquire.

What are Common Fentanyl Test Strip Brands?

Some of the most common fentanyl test strip brands include Rapid Response Fentanyl (FYL) Test Strips from BTNX Inc. (Canada), Rapid Self Test (RST) Fentanyl FYL20 from Rapid Self Test Inc. (Canada), Nal van Minden Drug-Screen FYL 10 (Germany), and One Step FYL20 Rapid Test Dipstick (China).14


  1. Legislative Analysis and Public Policy Association. (May 2021.) Fentanyl Test Strips.
  2. BTNX, Inc. (Accessed September 2021). Harm Reduction.
  3. RTI International. (Accessed September 2021). Infographic: Fentanyl Test Strips.
  4. Goldman, J.E., Waye, K.M., Periera, K.A. et al. Perspectives on rapid fentanyl test strips as a harm reduction practice among young adults who use drugs: a qualitative study. Harm Reduct J 16, 3 (2019).
  5. Substance Abuse and Mental Health Services Administration (SAMHSA). (April 2021). Federal Grantees May Now Use Funds to Purchase Fentanyl Test Strips.
  6. NYC.gov. (Accessed September 2021). Fentanyl Test Strip Instructional Brochure.
  7. Mass.gov. Prescription Dropbox Locations.
  8. U.S. Food & Drug Administration (FDA). Drug Disposal: FDA’s Flush List for Certain Medicines.
  9. National Harm Reduction Coalition. (August 2017). Fentanyl Test Strip Pilot.
  10. Green, T. C., Park, J. N., Gilbert, M., McKenzie, M., Struth, E., Lucas, R., Clarke, W., & Sherman, S. G. (2020). An assessment of the limits of detection, sensitivity and specificity of three devices for public health-based drug checking of fentanyl in street-acquired samples. The International journal on drug policy, 77, 102661.
  11. Mass.gov. (October 2018). Fentanyl Test Strips Reduce Risk Of Overdose In Small Study.
  12. Centers for Disease Control and Prevention (CDC). (July 2021). Fentanyl Facts.
  13. Griswold, M. K., Chai, P. R., Krotulski, A. J., Friscia, M., Chapman, B., Boyer, E. W., Logan, B. K., & Babu, K. M. (2018). Self-identification of nonpharmaceutical fentanyl exposure following heroin overdose. Clinical toxicology (Philadelphia, Pa.), 56(1), 37–42.
  14. Bergh, M. S., Øiestad, Å., Baumann, M. H., & Bogen, I. L. (2021). Selectivity and sensitivity of urine fentanyl test strips to detect fentanyl analogues in illicit drugs. The International journal on drug policy, 90, 103065.


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