The Four-Strip Safety Panel: Testing for Fentanyl, Nitazenes, Xylazine, and Medetomidine on One Sample

A fentanyl strip detects fentanyl. It doesn't detect nitazenes, xylazine, or medetomidine. Each of those requires its own immunoassay strip because the antibodies bind to specific molecular shapes, and those shapes are chemically unrelated.

If you're testing an opioid sample and only running a fentanyl strip, you have useful information, but you're not getting the full picture. The good news is that running all four strips on a single sample takes about 10 minutes, costs roughly $4.50 in materials, and uses the same procedure for each strip.

What You'll Need

• 1 fentanyl strip
• 1 nitazene strip
• 1 xylazine strip
• 1 medetomidine strip
• A clean container (a testing vial works well)
• Clean water
• About 15 mg of sample

Total material cost: roughly $4.50, less than a coffee.

The Protocol

Step 1: Dissolve

Place about 15 mg of your sample in a clean container. Add roughly 1/2 teaspoon (2.5 mL) of clean water and stir until dissolved. If it doesn't dissolve fully, the undissolved material is filler, test the dissolved portion.

Step 2: Dip, Fentanyl First

Dip the fentanyl strip with the arrows pointing down. The absorbent pad at the tip needs to be fully submerged. Hold for 10-15 seconds, then pull it out and lay it flat on a clean surface.

Set a timer for 3 minutes. Don't read it earlier than 2 minutes or later than 5.

Step 3: Dip, Nitazene Second

While waiting for the fentanyl strip, dip the nitazene strip in the same solution. The dissolved sample is still good, you don't need fresh solution for each strip.

Remove after 10-15 seconds and lay flat.

Step 4: Dip, Xylazine Third

Same procedure.

Step 5: Dip, Medetomidine Fourth

Medetomidine last.

Reading the Results

One line = positive. Two lines = negative. This is the opposite of a pregnancy test. If the control line (the top line) doesn't show, the strip is invalid, retest with a fresh one.

Interpreting Your Panel

— Sponsored —

Protect your connection while traveling

Common Mistakes

• Using too much sample. More sample does not make the test more sensitive, it can overload the strip and produce invalid results. Stick to ~10-15 mg.
• Reading too late. Strips left longer than 5 minutes can develop false positives as the membrane dries. Set a timer.
• Testing from one spot. Contaminants are not evenly distributed. If you have a gram, scrape from at least two different spots and test each separately.
• Skipping strips to save money. A fentanyl-only test misses the other three. The full panel costs $4.50, a fraction of what you paid for the substance itself.

The Bottom Line

Running four strips instead of one triples your material cost (from $0.44 to ~$4.50) but multiplies your coverage by four. For anyone using opioids, testing counterfeit pills, or buying from an unfamiliar source, the panel is the minimum responsible protocol in 2026.

The complete opioid test kit bundles all four strips at a small discount if you want to stock the full panel at once.

Further reading: Nitazenes guide | Xylazine guide | Fentanyl strips guide

Disclosure: this article contains affiliate links, we may earn a commission at no extra cost to you. Testing reduces risk; it never eliminates it. Immunoassay strips are screening tools, a negative result is not a guarantee of absence.