How to Test Your Drugs for Fentanyl

Test strips are easy to use and can turn up synthetic opioids in heroin, cocaine, and other powders before you actually put them in your body.
an illustration of fentanyl test strips
Illustration by Cathryn Virginia
Real information about using drugs and alcohol.

If you use opioids, coke, meth, or other illegal drugs, you might want to be extra-cautious that you’re taking what you think you are right now. Luckily, there’s a common, easy, and cheap way to do that—we’ll get into drug testing strips in a second, but in terms of why you’d bother with them to begin with, let’s talk about fentanyl. 

Though the synthetic opioid fentanyl is far and away most commonly found as an adulterant in heroin, growing evidence suggests that other drugs—including counterfeit pharmaceutical pills, cocaine, benzodiazepine, and methamphetamine—are increasingly contaminated with it. (It’s not always clear at which stage in the drug supply chain that fentanyl comes in contact with a given substance.) In April 2021, eight percent of cocaine tested by the police in New York City was adulterated with fentanyl—up from two percent in 2017—which is the equivalent of nearly one in every 10 bags of coke.


Even if a drug doesn’t contain a lot of fentanyl, it’s still dangerous. Fentanyl is 50 to 100 times more potent than morphine, and two milligrams is considered a lethal dose (and even more so if a person isn’t accustomed to using opioids). Provisional data from the Centers for Disease Control reflect over 81,000 overdose deaths between June 2019 and May 2020, the highest number ever recorded in a single year. According to the CDC, “Synthetic opioids (primarily illicitly manufactured fentanyl) appear to be the primary driver of the increases in overdose deaths, increasing 38.4 percent.” The agency also noted that cocaine-related overdoses have increased, which is likely related to coingestion with opioids, either through contamination or co-use.

Even if you know your dealer or otherwise feel confident about what you’re buying, you can’t eyeball or taste your drugs to tell whether they’re solely what they’re supposed to be: Fentanyl can take many forms, including a white powder, so it’s not always detectable by sight or taste. Instead, people are testing their drugs at home with fentanyl test strips to see if they’ve come in contact with or are cut with synthetic opioids.

“Given the current state of the drug market, we recommend that folks test all drugs with fentanyl test strips,” said Kristin Karas, chief operating officer at the harm-reduction organization DanceSafe. To keep yourself a little safer as you use, here’s how to add a small step into your drug use that might make an enormous difference for your well-being.


What do fentanyl test strips do?

A fentanyl test strip is a little strip of paper that changes color based on whether it’s placed in liquid containing fentanyl. Fentanyl test strips can be bought individually or in testing kits containing test tubes for mixing, a buffer solution to dissolve the drugs, and some Q-tips for stirring. (If you don’t have a kit, you can use water instead of a buffer solution and a small glass.)

There are multiple kinds of fentanyl analogs, the most common being carfentanil, along with 25 or so less common kinds, including methylfentanyl, furanylfentanyl, and acrylfentanyl, according to James Giordano, professor of neurology and biochemistry at Georgetown University Medical Center. Fentanyl test strips pick up on the most common kinds of fentanyl about 97 percent of the time, so the user can avoid taking the substance, or, if they’re still intent on taking it, reduce the amount they take.

“When people know there's fentanyl in the substance they plan on using, they can adjust the way they use in a way that makes them less likely to overdose,” said Ricky Bluthenthal, professor of preventive medicine at the Keck School of Medicine of the University of Southern California. “They can use slower, they can start with a smaller dose than they might ordinarily use, or they can decide not to use it.” (Although it’s best not to use drugs that test positive for fentanyl at all, if you choose to go ahead with it, make sure you’ve got overdose-reversing naloxone nasal spray on hand, as well as someone capable of administering it.)


What don’t fentanyl test strips pick up?

A test strip shouldn’t be considered a potential “all clear” that drugs don’t have fentanyl in them, but an extra precaution. It’s entirely possible for a test to come back negative when a drug has a less apparent kind of fentanyl in it: Depending on the quality of the test strips you’re using, they might only test for the most common variations, said Jonathan Caulkins, professor of operations research and public policy at the Heinz College of Information Systems and Public Policy at Carnegie Mellon University. “There are different kinds of fentanyl, and there are even other novel synthetic opioids that are not. strictly speaking, a fentanyl at all, but they are sort of similar chemically, and very similar practically,” he said. 

Even though many tests are sensitive, if you test just a portion of the drugs, the fentanyl may be hiding elsewhere. “The fentanyl may not be evenly distributed in the sample, so you could test it and it could be negative, but there could be fentanyl in other parts of the substance,” said Bluthenthal.

More advanced fentanyl detection may be available via drug-checking services such as Energy Control and Drugs Data, each of which send your substance off to a lab to be tested for contaminants if you mail them in. “Some of these types of organizations use more in-depth, scientific tests like mass spectrometry, and these types of tests can be more valid and reliable than quick-screening tests like fentanyl test strips,” said Brian Wind, clinical psychologist and chief clinical officer for the addiction center JourneyPure, though these tests are still not guaranteed to detect every kind of fentanyl analog. 


Some community programs also offer drug-checking services, which you can find by Googling “community drug evaluation services and resources” and the name of your city, said Giordano. 

Where do I get fentanyl test strips?

You can get fentanyl test strips through syringe service programs and other community harm reduction programs listed on local health department websites, according to Wind. It’s also possible to order fentanyl test strips online through DanceSafe. These tests, made by the brand BTNX, have been verified to test 13 kinds of fentanyl (which is still by no means all kinds, but is better than nothing). Buying testing strips from unverified sources online, like Amazon, may result in lower-quality or unreliable tests.

How do I use fentanyl test strips?

Once you have a kit, or strips and your own supplies, you mix either all or a portion of the drug you’re using (more on that below) with water or buffer solution and dip in the strip for 15 seconds, then check if there are two red lines (indicating the drugs have tested negative for the kinds of fentanyl it can detect) or one red line (meaning there is fentanyl in the drug). “If no red lines appear, it means the test is invalid and you should redo it,” said Jaydeep Tripathy, a primary care doctor at Doctor Spring.

DanceSafe recommends that, if possible, you test the entire sample. This involves dissolving all of your drugs in water—if you do that, you’ll need to drink your dose, so you’ll want to get the ratio of drugs to liquid right. With MDMA or methamphetamine, for instance, you’d use about a teaspoon of water for every 10mg you test. With cocaine or other powder drugs, you’d use two teaspoons of water for every 100mg of powder. To test a pressed pill, you’d add just enough water to dissolve a crushed tablet. (Many kits include instructions, by the way, so don't feel like you need to memorize this info now.)


To some people, the idea of taking all their drugs in liquid form might sound unrealistic or inconvenient. If you don’t want to test the entirety of your drugs, you could try a compromise: Because reliable test strips, like the BTNX ones, are sensitive enough to pick up nanograms of fentanyl, dumping out powder drugs from their baggies and using the traces left inside to make a solution is another (although less effective) method for testing the drugs. 

Leland Radovanovic, a 30-year-old communications professional living in Massachusetts, got fentanyl test strips from a harm reduction organization called the Washington Heights CORNER Project while living in New York and used them to test MDMA and cocaine; his results were negative. “What I normally do is empty the bag, then put a little water in the bag to make a solution and then test the solution,” he said. “That way, I don't have to waste a bunch.” 

This approach, though less surefire, still makes sense, said Giordano, because “you break the volume down into solution and aerate it in the baggie, which makes it viable for detection.” 

Even though Radovanovic’s tests were negative, he’s still happy he made the choice to test. “This seemed like a smart thing to do, and I’m super glad I did,” he added. “Unfortunately, unregulated drugs are a mystery, even when you get [them] from a reputable dealer.” Indeed, even if a dealer is someone you know, they themselves can’t be sure if they’re getting a contaminated batch. 

As one 43-year-old business owner in Los Angeles who tests his drugs and asked VICE not to disclose his name for legal reasons said, “It was pretty easy… the whole process took maybe five minutes.” There's truly no downside to testing—and you’re always better off safe than sorry. Whichever method you use, you’re still more likely to find out whether synthetic opioids are in your drugs than if you hadn’t tested—just before you use your drugs, instead of after.

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