How to test your drugs for fentanyl

When testing your drugs for fentanyl, it is very important to follow the instructions exactly.

Use the information below to determine the right dilution for the form of drug you’re testing, and wait a full three minutes before assessing the results. While there are only three basic steps to this process, correctly diluting your drugs is very important to ensure that your results are accurate.


  1. No fentanyl test strip on the market can detect every fentanyl analog.
  2. At the moment, there are no strips that can detect non-fentanyl synthetic opioids like isotonitazene.

A negative result does not guarantee that your drug sample is free from all synthetic opioids.


STEP 1: Preparing and diluting your drugs

Whether you are testing everything you intend to consume or a smaller portion of your drugs, you need to dilute the powder in the correct amount of water.

Open the tab and follow the instructions below for each type of drug.

Crystals or Powdered Drugs

Pharmaceutical Pills

Pressed Ecstasy Tablets

Blotter LSD

IV Drugs

STEP 2: Using the strips

After you have diluted your drug using our instructions above, it’s time to use the strips.

1. Hold the yellow end of the test strip and insert the other end into the liquid.

2. Allow the liquid to travel up the strip into the test area for a full 15 seconds.

3. Remove the strip and set it down on a flat surface. Wait about three minutes.

holding fentanyl test strips

STEP 3: Interpreting the results

One red line on top (closer to the yellow end) after waiting three minutes is a POSITIVE result for the presence of fentanyl. Two red lines is a NEGATIVE result.

  • The lower red line may be significantly lighter than the upper red line. If you can see it at all after waiting three minutes, no matter how faint, it is still a negative result.
  • No red lines (or one red line on the bottom, closer to the dotted end) means the test is invalid. Usually this happens because the liquid did not travel far enough up the test strip.
fentanyl test strips results

IMPORTANT! Sometimes a very faint red line will initially appear in the lower area, then quickly fade away. Do NOT confuse this with a negative result. Always wait three minutes before interpreting the results.

Additional Instructions

Getting your powder back

Fentanyl strip testing does NOT destroy your drugs.

You can get your powder back by evaporating away the water. There are many ways to do this, but one of the most popular is pouring the water into a flat-bottomed glass or ceramic dish (like a Pyrex pie dish) and heating it. Other methods involve double boilers, air evaporation (for small quantities), or even blow driers. The most popular method is using an oven.

  1. Put the pan in the oven on the lowest heat setting, no higher than 225 degrees F.
  2. Keep the oven door cracked and keep a close eye on the pan. This process can take minutes to hours depending on how much water you’re evaporating.
  3. When all the water has evaporated, a film/residue will appear on the bottom of the pan. Take the pan out and let it cool.
    1. This residue usually looks a bit like a thin layer of ice or splotchy crystalline patterns.
  4. Scrape up the residue using a straight razor or other sharp tool.
    1. If it’s not fully dry, your powder might be a little tacky or goopy.

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. If your drugs weren’t brown to begin with, a tan or brown tint might mean that you’ve burned them.

Understanding & Preventing Overdoses

Except for suicides, overdose deaths are always accidental. The word “overdose” has sometimes carried a moral judgment that the individual was “pushing their limits” in order to get as high as possible, as if it were their own fault.

This is not true. “Overdose” simply means taking too much of a drug, and it is always accidental. Even daily opioid users who know that fentanyl is in their product have no way of knowing the amount.

Instead of blaming others, let’s work together to end accidental overdoses.