How to Test for Fentanyl
How to Test for Fentanyl
Testing anything not from a pharmacy? Start here
Fentanyl test strips screen a sample for fentanyl and many of its analogs, which is information you can't get any other way at home. They can't make a sample safe, and a negative result speaks only for the portion you tested. Dilution decides whether the result means anything, so read the steps below closely and follow them.
Fentanyl is a synthetic opioid, roughly 100 times stronger than morphine and 50 times more potent than heroin, and since 2018 it's been the dominant opioid in the illegal market. It's sold as a powder and pressed into pills, including counterfeits of painkillers like Oxycontin, Vicodin and Percocet and benzodiazepines like Xanax and Valium. It also turns up cut into cocaine, heroin and many other substances, usually without the buyer knowing, and that unknowing consumption is what drives so many overdoses.
The tool on this page is the fentanyl test strip, an antibody-based test that screens a diluted sample for fentanyl and many of its analogs. It screens; it doesn't measure how much is present or name which opioid you have, and a negative describes only the exact portion you dissolved and tested. It won't catch nitazenes or xylazine, and because fentanyl is rarely mixed evenly, the strip's answer stops at the material you actually put in the water.
Common fentanyl terminology
New to this? These are the words the rest of the page uses. Tap any term to expand it.
Fentanyl
A synthetic opioid roughly 100 times stronger than morphine and 50 times stronger than heroin, and the dominant opioid in the illegal market since 2018. It shows up in powders and pressed pills, including substances sold as something else entirely.
Fentanyl analog
A close chemical relative of fentanyl. The strips detect many known analogs, but some can still read negative, so a clear result isn't proof the sample is opioid-free.
Adulterant (cut)
Something mixed into a drug that the buyer didn't ask for. Fentanyl is a common adulterant in cocaine, heroin and counterfeit pills; the strip screens for fentanyl specifically and can't flag other adulterants.
Nitazenes
A separate family of potent synthetic opioids. Fentanyl test strips don't detect them, so ruling out nitazenes takes separate nitazene strips.
Xylazine
A non-opioid sedative found cut into some opioid supplies. A fentanyl strip won't see it; testing for it takes Xyl strips.
Fentanyl test strip (immunoassay)
An antibody-based strip that screens a diluted sample for fentanyl and most analogs. It screens rather than confirms: it can't say how much is present or name the exact compound, and only laboratory analysis confirms what a sample contains.
False negative
A negative reading on a sample that actually contains fentanyl. Over-diluting the mixture, an analog the strip doesn't catch, or fentanyl clumped in a part you didn't test can all produce one, which is why testing only covers the portion tested.
Chocolate chip cookie effect
The uneven way fentanyl mixes into other substances: one or more deadly doses can clump in one spot while the rest carries none. It's the reason testing everything you plan to consume beats testing a pinch.
Counterfeit pills ("fentapills")
Pressed fakes made to look exactly like real pharmaceuticals such as Oxycontin or Vicodin. Looks tell you nothing, so anything you didn't get from a pharmacy yourself has to be tested.
Presumptive
A result that points toward an answer without proving it. At-home reagents and strips are presumptive; only laboratory analysis confirms what a sample actually is.
Fentanyl and its many analogs are highly potent synthetic opioids. Fentanyl is about 100 times stronger than morphine and 50 times more potent than heroin. Unknowing consumption of fentanyl is largely responsible for the surge in overdose and drug-related deaths worldwide, and fentanyl overdose has been reported as the number one cause of death for Americans aged 18 to 45.
These deaths are linked to fentanyl-laced counterfeit pharmaceutical pills, painkillers like Oxycontin, Vicodin or Percocet, and benzodiazepines like Xanax or Valium, as well as fentanyl-laced cocaine, heroin and many other substances. People are unknowingly consuming fentanyl and overdosing, in part because they don't know what their substance actually contains.
Because of the widespread use of fentanyl in drug manufacturing, it is impossible to know if a drug is fentanyl-free without testing it. If you did not personally obtain your substance from a pharmacy, it must be tested for fentanyl.
Suggested order for fully testing your substance
Use our fentanyl test strips together with our spot kits and separation kits to evaluate your sample thoroughly. FentKits are designed to detect fentanyl and its analogs; they cannot detect other dangerous adulterants, which is what the reagent kits are for.
- First, set a very small sample aside (which you will later use for reagent testing).
- Test using FentKits: Read the instructions, and, ideally, dissolve and test all of the drug you plan to take, not just a sample of it, using our FentKits. If you do not intend to test the entire portion of your substance, please see the "Backup Method" below for testing a portion of your drugs.
- Test using reagents (Spot Kit / Separation Kit): Take the sample you set aside, and test for adulterants using our spot kit packages / separation kits. This small sample cannot be consumed, and must be discarded after testing. For more information on how to do this / which to use, please see the Our Types of Kits page.
About our strips: W.H.P.M. fentanyl test strips
We now stock the light blue W.H.P.M. fentanyl test strips. They detect fentanyl and many of its known analogs in a diluted drug sample, and unlike some other strips on the market, they do not produce false positives with meth, MDMA, or cocaine that contains levamisole, so they can also be used to test pressed ecstasy tablets. They use an antibody with high specificity to fentanyl. What they can't do is name a molecule, measure how much is present, or catch every novel opioid: they miss nitazenes and some fentanyl analogs, and a negative describes only the portion you tested.
Our fentanyl test strips are manufactured by the Irwindale, California company W.H.P.M., and assessed in the laboratory for their sensitivity and specificity to fentanyl, its analogs, and for potential false positives.
Note: Our light blue strips are the exact same strips as the DanceSafe yellow test strips!
Please read carefully (at least twice) and follow the full instructions closely! To find instructions for the older, dark blue, BTNX fentanyl test strips (which we no longer sell), see the old strip instructions. Those instructions have different dilution ratios than our new strips!
Important: the "chocolate chip cookie effect"
When fentanyl is contaminating other substances, it is rarely mixed evenly. One or more deadly doses may be clumped up in one part of the baggie, while most of the baggie might contain no fentanyl at all. This is known as the "chocolate chip cookie effect," and it explains why it is ideal to test everything you plan to consume.
You will need to dissolve your entire dose in water. If the test comes back negative, you can drink the water after testing — the strips do not contaminate the water. If you are testing cocaine or other drugs that you want to snort or smoke, you can get the powder back by evaporating the water.
Crush any crystals or rocks into a fine powder and mix as thoroughly as possible. Emptying the powder on a plate and stirring it for five minutes is more effective than shaking the baggie. This attempts to disperse any potential fentanyl as evenly as possible throughout the baggie, to increase the likelihood that some fentanyl is present in the small portion you decide to test.
Step 1: Preparing and diluting your drugs
This is the most important step. Read carefully and dilute correctly. These instructions only work for the fentanyl test strips manufactured by W.H.P.M. Other strips on the market contain different antibodies and may not work for drug checking.
For crystal or powdered drugs
- Weigh your drugs. Use a milligram scale to get the weight of the crystals or powder you are going to test. Write it down so you don't forget. If you don't have a milligram scale, you can use one of our 10 mg measuring spoons.
- Place your drugs in a small container. A standard 20 oz soda bottle cap holds about 1 teaspoon (5 ml), enough water for 10 mg of most powders. For larger amounts, use a small glass or ceramic cup.
- Add 1 teaspoon (5 ml) of water for every 10 mg of powder (one level micro scoop). For meth or MDMA, use twice as much water: 2 teaspoons (10 ml) for every 10 mg. If meth or MDMA tests positive, add more water and test again.
- Stir the mixture until completely dissolved. Proceed to STEP 2!
A level scoop (not rounded) of finely crushed powder is approx. 10 milligrams (available at TransparencyTestKits.com). One level micro scoop into a capful of water works well. For meth or MDMA, use two capfuls.
| Powder | Water (most powders) | Water (meth and MDMA) |
|---|---|---|
| 10 mg | into 5 ml | into 10 ml |
| 20 mg | into 10 ml | into 20 ml |
| 50 mg | into 25 ml | into 50 ml |
| 100 mg | into 50 ml | into 100 ml |
| 1 gram | into 500 ml | into 1 litre |
For pharmaceutical pills & pressed MDMA "ecstasy" tablets
- Crush the entire tablet into a fine powder.
- Pour the powder into a small cup.
- Add approximately 4 tablespoons (or 1/4 cup) of water.
- Stir the mixture well. Proceed to STEP 2! Binder material may not completely dissolve — that's okay.
Only W.H.P.M. fentanyl test strips work on pressed ecstasy tablets. Other strips give false positives.
Counterfeit pharmaceutical pills often look exactly like the real ones. If you don't have a prescription yourself, always test them for fentanyl first. Oxycontin and Vicodin are some of the more popular "fentapills" on the market.
For people who inject drugs
If you inject heroin or other drugs, you should test every time you inject. The easiest method is to test the residue from your spoon or cooker.
- After preparing your shot, set the needle aside and wait to inject.
- Add about 1 ml of clean water into the spoon or cooker. Proceed to STEP 2!
Step 2: Using the strips
After following STEP 1 to dilute your drugs, it's time to use the strips.
- Hold the blue end of the test strip and insert the other end into the liquid, no higher than the top of the dotted section. Do not insert above the dotted section — the water travels up the strip into the test area.
- Hold the strip in the liquid for a full 15 seconds.
- Set the strip on a flat surface and wait three minutes before reading the result. Don't read it after 10 minutes. Proceed to STEP 3!
Step 3: Interpreting the results
One red line on top after waiting 3 minutes is POSITIVE for fentanyl. That's strong evidence fentanyl is present in the portion you tested; treat the whole sample as containing it.
Two red lines is NEGATIVE for fentanyl in the portion you tested. Note that the lower red line may be much lighter than the upper line. If you can see any line at all after three minutes, no matter how faint it may be, this is still negative for fentanyl.
Usually this happens because the liquid did not travel far enough up the test strip.
- Use a bright light.
- Any second line, no matter how faint, is still a negative result.
Getting your powder back
Fentanyl test strips do not contaminate your drugs. You can dilute your entire batch in water, test it, and then evaporate the water to get your powder back. Use a flat-bottomed, glass baking pan (like a Pyrex® dish) and heat it on low in an oven.
- Place the pan on the center rack, and set the oven no higher than 225°F.
- Keep the oven door slightly open and wait for the water to evaporate. This process can take minutes to hours, depending on how much water you used.
- When all the water has evaporated, there will be a light residue on the bottom of the pan. Take it out and let it cool.
- Now simply scrape up the residue using a sharp, flat tool. A straight razor works best, but a credit card or knife also work.
Don't leave your drugs in the oven for too long after they're dry. They won't burn right away, but they will eventually.
WARNING! These test strips do not guarantee that your substances are free of synthetic opioids. They do not detect nitazenes, which need separate nitazene strips, and a negative only describes the portion you tested.
What is fentanyl?
Fentanyl is a synthetic opioid 50 times stronger than heroin. Since 2018, it has become the dominant opioid in the illegal market. Found in pills and powders, including non-opioids and counterfeit pharmaceutical pills, fentanyl is responsible for tens of thousands of deaths a year in the U.S. alone.
Instructions for the old (dark blue) BTNX fentanyl test strips can be found here. Note that they use different dilution ratios than the current strips.
Questions
The second line is really faint. Is that a positive?
No, the opposite is true. Any second line, no matter how faint, is still a negative result. The lower red line is often much lighter than the upper line. Use a bright light, wait the full three minutes, and if you can see any line at all, the test is negative for fentanyl in the portion you tested.
No lines appeared at all. What happened?
No red lines (or one red line on the bottom) means the test is invalid. Usually this happens because the liquid did not travel far enough up the test strip. Re-run with a fresh strip, making sure you insert it no higher than the top of the dotted section and hold it in the liquid for a full 15 seconds.
How much water do I use?
Most powders: 10 mg in 1 teaspoon (5 ml). Meth and MDMA: 10 mg in 2 teaspoons (10 ml). Pressed pill: crush the whole pill into about 1/4 cup. Getting this wrong is the most common testing mistake: too little water can cause false positives, and too much water can hide a very small amount of fentanyl. Don't eyeball it; use the micro scoop and measuring cup in the FentKit.
Do I lose my drugs by testing them?
No. Fentanyl test strips do not contaminate your drugs. If the test comes back negative you can drink the water, or evaporate it in a glass pan in a low oven (no higher than 225°F) and scrape up the residue. The full method is in "Getting your powder back" above.
Can I test pressed pills with these strips?
Yes. Crush the entire tablet, add approximately 4 tablespoons (1/4 cup) of water, and stir. Note that only W.H.P.M. fentanyl test strips work on pressed ecstasy tablets, because other strips give false positives. Binder material may not completely dissolve, and that's okay.
Do these strips give false positives with meth, MDMA or cocaine?
Unlike some other strips on the market, our W.H.P.M. strips do not produce false positives with meth, MDMA, or cocaine that contains levamisole, provided you dilute correctly. Meth and MDMA need twice the usual water: 10 mg in 2 teaspoons (10 ml). If meth or MDMA tests positive, add more water and test again. Over-concentrating any drug solution can still push a strip toward a false positive.
Do fentanyl strips detect nitazenes or xylazine?
No. Nitazenes need separate nitazene strips and xylazine needs Xyl strips. Some fentanyl analogs and novel synthetic opioids can also read negative.
Does a negative result mean my drugs are safe?
No. A negative describes only the portion you tested, at the dilution you used. Fentanyl is rarely mixed evenly, the "chocolate chip cookie effect," which is why the best method is dissolving and testing everything you plan to consume. And no strip can tell you what else is in the sample; that's what spot kits and lab testing are for.
I have the old dark blue strips. Do these instructions apply?
No. The older, dark blue BTNX strips use different dilution ratios. Their instructions are here. We no longer sell them.
FentKits — fentanyl test strips with measuring tools
Strips plus the micro scoop and measuring cup you need to dilute correctly. Orders ship within 24 hours.
Free shipping over $75 · Discreet packaging
More resources
- How to test for nitazenes: fentanyl strips do not detect these
- How to test for xylazine
- How to test heroin and pain pills
- Our types of test kits
- Old (dark blue) BTNX strip instructions
- Lab testing with Transparency Testing: for the questions strips can't answer
A sample that has been tested should not be considered safe. There is inherent risk when choosing to consume any substance.
Many factors are involved when conducting a test and examining reactions, and The Bunk Police does not assume responsibility for the interpretation of results. Reactions of individual samples can vary depending on lighting differences and the specific mixtures of substances being tested.
Bunk Police kits are intended for identifying unknown substances for harm reduction purposes only. The Bunk Police does not assume responsibility for the use or misuse of this information. Proceed at your own risk.
