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About this test
The most sensitive, cost-effective, and accessible method for checking if your drugs contain fentanyl is by using Fentanyl Test Strips.
These strips were originally developed to test for fentanyl in urine, and have been found to work equally well for detecting fentanyl in any sample. The test strips that we sell here at DoseTest are the most reliable on the market.
Whatever your choice of drug is, Fentanyl is more and more frequently popping up in samples such as Cocaine and Amphetamine, using these low-cost testing strips is the easiest way to ascertain whether or not your sample contains Fentanyl. </strong
We recommend two different ways of testing, depending on if you have a solid or liquid sample.
1: Prepare your sample
Pills and powders: If testing a pill, break off a small chunk and crush it as finely as you can. If it’s a powder, chop it up and mix it as best you can. These strips are highly sensitive, so you only need about 50 milligrams (think a couple of grains of salt). Put this into a cup, add 5ml (about a teaspoon) of water and mix them together. Fentanyl dissolves pretty easily, so don’t worry if there is some residue after you’ve stirred it a bit – that won’t affect the results.
(Note: MDMA and methamphetamine can cause false positives. To avoid this, add an extra 4 tsp to the sample so that it is more diluted. IPPH and DPH can also cause false positives, but are far less common).
Liquid: If you’re prepping a shot, do that first – the residue left in the preparation container is all you need. Add about 5ml of water (about a teaspoon), then put the mix into a cup. If it’s in a vial/bottle, shake it a little and put a drop into a cup, then add the teaspoon of water and mix.. If you are testing a pressed tablet or pill, using a clean knife, break off a small part and crush it into a powder. If your substance is already in the form of a powder, mix it as thoroughly as possible.
2: Running your test
Take the strip out of its packaging, then dip the end with the wavy lines into your sample for about 15 seconds. Once that’s done, place it horizontally on a nice clean surface and wait for up to 3 minutes for your results to appear.
3: Interpreting your test
Since there are 2 lines which would either appear or not appear, there are 4 possible results. The line nearer the end that you dipped is the Test line, and the line nearer the handle is the Control line.
Control line visible, Test line invisible: This is a positive result, which indicates that your sample DOES contain fentanyl.
Control line visible, Test line visible: This is a negative result, which indicates that your sample DOES NOT contain fentanyl.
Control line invisible: Regardless of what the Test line does, this means that something has gone wrong and the result is inconclusive – we don’t know if your sample contains fentanyl. We advise repeating the test or, if that isn’t possible, assuming that the sample DOES CONTAIN fentanyl.
False positives
Methamphetamine and MDMA are two drugs that can cause false positives with fentanyl test strips. When testing these substances it is important to make sure your dilution is about 1 mg/mL. Using the above protocols, false positives should be minimized, however if you are testing one of these substances and obtain a positive result, it is recommended to increase your dilution and test again with a new test strip. If the second test is also positive for fentanyl, it should be assumed that fentanyl is present in your sample.
Other substances that may cause false positives:
Isopropylphenidate or IPPH
Diphenhydramine
Different results for the same sample
If two different results are read for the same sample, repeat the test again. As such a small amount of the sample is tested, and as solid samples such as pressed pills or powders might not be homogenous, it is possible that fentanyl may be present in your sample only in one area of the pill or baggie. This is why it is best to test more than one area of a pill or of a powder and to mix your sample as much as possible before testing! It may be wise to test a larger quantity of your substance, which will allow for a more accurate representation of your sample. To do this you would dissolve 15 mg of your sample (0.015 g) in 15 mL (1 tablespoon) of tap water. Keep a ratio of 1 mg sample to 1 mL water to reach the optimal zone well above the detection limit of the strips and below the area where other compounds in the sample could produce a false result.
Faint second line
Sometimes after dipping the strip in the test solution a faint second line appears, leading to confusion when interpreting the result. Most harm reduction organizations assert that any second line, no matter how faint, should be interpreted as negative (3). For the minimization of risk, we recommend re-testing your sample with a new test strip if you are unsure of how to interpret the result.
Control line does not show up
If the control line, which is the top line when the strip is held with the wavy side at the bottom, does not appear, it means the fentanyl test strip is defective and should be discarded. Test again using a new strip.


Together we can save lives ❤️


DoseTest is here to shake up the harm reduction world, taking lifesaving materials like reagent test kits and fentanyl test strips from the small niche where they have lived and making them accessible to everyone. This doesn’t just mean selling them cheaper than everyone else, though. It means meeting people where they are and advancing both the materials and the information about how and why to use them. It means working together with everyone from state health departments to mutual aid groups to reach people that we never could alone.