What Are Fentanyl Test Strips?

We now offer free fentanyl test strips by mail to Tennessee residents! To learn more, visit How to Request Supplies via Mail.

Fentanyl test strips are small strips of specialized paper that inform us of the presence of fentanyl in samples of drugs and urine.

Similar to dipstick pregnancy tests or instant urine drug screens, fentanyl test strips display red lines to show positive or negative readings. Positive results show one line; negative results show two lines.

How do fentanyl test strips prevent overdose?

Fentanyl test strips provide people who use drugs with crucial information that can help prevent drug overdose. Drug users who get positive test results are likely to adopt safer drug use behavior.

One International Journal of Drug Policy study shows people who inject drugs who received a positive test result were five times more likely to change their drug use behavior than those with a negative result. Such behavior changes include:

  • Trying new batches of drugs with small test doses
  • Only using drugs when around a friend with naloxone (e.g., NARCAN®)
  • Disposing of the drugs that tested positive
  • Informing suppliers of the positive results, and finding new sources to get uncontaminated drugs from

How to use fentanyl test strips

Here’s how to test for fentanyl in a sample of drugs:

  1. Crush drugs into a fine powder.
    • If injecting drugs, prepare your shot as normal and proceed to step two.
  2. Mix drugs with water.
    • WARNING: Some substances can cause false positives. To minimize the risk of false positive results, different drugs require different amounts of water (dilution).
      • If using WiseBatch strips, visit their website’s Resource page for dilution instructions.
      • If using DanceSafe strips, visit their website’s “New Fentanyl Test Strips” page for dilution instructions.
      • If using Dosetest strips, visit their website’s “Fentanyl Test Strip App” page for dilution instructions.
      • If using BTNX “Rapid Response” strips, DanceSafe’s “Older Fentanyl Strips” page has dilution instructions.
  3. Dip test strip into water.
  4. Lay strip aside and await results.

Are fentanyl test strips legal in Tennessee?

Yes, fentanyl test strips are legal in Tennessee — except when used in the manufacture, delivery, or sale of a controlled substance, per Tenn. Code Ann. § 39-17-417.

On March 31, 2022, Tennessee Governor Bill Lee signed HB 2177/SB 2427 into law, removing “narcotic testing equipment used to determine whether a controlled substance contains a synthetic opioid” (like fentanyl test strips) from Tenn. Code Ann. § 39-17-402(12)(B) — the statute that defines “drug paraphernalia.”

What you should know about the fentanyl test strip market

Today, more than a dozen brands of fentanyl test strips are available to consumers. Although they all promise high degrees of reliability, the truth isn’t as glamorous.

Many show false positives for substances commonly found in illicit drugs, aren’t as sensitive as they claim to be, and can have high lot-to-lot variability (i.e., two strips from the same brand may not work the same).

When harm reduction organizations began using FTS to test drug samples around 2017, test strips manufactured by AssureTech, a Chinese company, became the industry standard. Initially, AssureTech strips were only available through BTNX, a Canadian FTS brand, who sells the green “Rapid Response” tests. In recent years, other brands have begun selling AssureTech strips, including WiseBatch and Dosetest.

In late 2022, DanceSafe began selling fentanyl test strips from a new manufacturer — WHPM. While DanceSafe claims these strips are superior to AssureTech’s, we’re not sure what to believe. We’re waiting for more independent research to come out before we support these claims.

Sadly, the FTS market is shrouded in mystery and misunderstanding. Brands rarely — if ever — manufacture their own strips, usually never disclose who manufactures them, and often fail to include instructions for testing illicit drugs.

That said, we feel compelled to support fentanyl test strip brands that:

  1. Are clear about where their test strips come from
  2. Include on-package instructions
  3. Make in-depth instructions available on their websites

What brands of fentanyl test strips are available?

We only recommend a few brands: WiseBatch, DanceSafe, Dosetest, and BTNX “Rapid Response” fentanyl test strips — the image below summarizes our findings and opinions on each of these brands:

Where can I find fentanyl test strips for sale?

While you probably won’t find fentanyl test strips for sale in Walgreens, CVS, or any other brick-and-mortar stores anytime soon, a quick google search will reveal dozens of places to buy fentanyl test strips. Again, we strongly recommend only buying the four brands listed above.

If possible, buy your strips directly from the brand you’re looking for. Three of our recommended brands sell their strips directly to consumers: DanceSafe, WiseBatch, and Dosetest.

BrandPrice if you buy 1…10…25…100…
Prices listed are per-strip

Where can I find free fentanyl test strips in Tennessee?

We offer a supply-by-mail program to Tennessee residents! The supplies are free, but we do ask you to cover shipping.

The only other way to get free fentanyl test strips in Tennessee is through the Tennessee Department of Health. Beginning in November 2022, TDoH began providing test strips to Syringe Services Programs (SSPs) and Regional Overdose Prevention Specialists (ROPS). Since then, we’ve talked to several ROPS and a few SSPs about this FTS rollout.

READ MORE: What Do Tennessee’s Regional Overdose Prevention Specialists Do?

Some ROPS have received brands of strips that we do not recommend. Some ROPS tell us they had strips at one point, but didn’t have any when we contacted them. None of the ROPS or SSPs we talked to mentioned having instructions for dilution (i.e., using different amounts of water when testing different drugs to avoid bad results).

For these reasons, tread carefully when sourcing FTS from ROPS or state-approved SSPs. If you decide to source test strips from ROPS or SSPs, we recommend:

  1. Only using one of our four recommended brands
  2. Always following the manufacturer’s instructions for dilution

Best practices for preventing drug overdose deaths

  • Embrace drug checking. Drug checking — commonly confused with drug testing — helps people figure out what substances their drugs contain, reducing the risk of overdose and other adverse reactions. Examples of drug checking tools include fentanyl test strips, drug reagents, and having your drugs lab-tested.

    • DID YOU KNOW? In partnership with the University of North Carolina, we collect samples of drugs from three cities — Nashville, Murfreesboro, and Jackson — and have them lab-tested at UNC’s Street Drug Analysis Lab. As of January 2022, we’ve had 29 samples tested. Better yet, the results are available publicly!

  • Keep naloxone around. Even if you get a negative result, fentanyl test strips are not a replacement for naloxone. Keep naloxone in your car, at home, and everywhere else you go in a day’s time.

    • DID YOU KNOW? Our supply-by-mail program offers free naloxone to Tennessee residents — you just pay shipping. Visit How to Request Supplies via Mail to learn more.

  • Don’t mix drugs. Most drug-related deaths occur from combined drug intoxication (i.e., mixing two or more drugs). If you use drugs, try your best to only take one substance at a time. If you decide to combine drugs, use this drug combination reference app from TripSit to help you avoid particularly dangerous drug interactions.

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