This page was last updated June 1, 2023
Xylazine, also known as “tranq,” is a veterinary tranquilizer that is increasingly being added to illicitly sold opioids such as fentanyl and heroin. Xylazine causes very strong drowsiness that can make it difficult or impossible for people to stay awake. When xylazine is found alongside opioids, the combined sedation can increase the risk of an adverse medical incident or overdose. Repeat exposure to xylazine is also associated with skin problems like ulcers, abscesses, necrosis, and other complications. These may appear far away from injection sites, and can also happen via smoking, snorting, swallowing, and other routes of administration.
Right now we are only offering xylazine test strips to institutional wholesale customers. They cost $0.89 each with a minimum purchase of 100 strips. This is a pre-order special. (We will begin shipping the strips at the end of June.)
If you are a state or county health department, syringe service provider, drug checking program or other social service agency, and if you already have an account registered with us, you can buy them here. If you have not yet registered a wholesale account, please start by clicking here.
It’s All About Dilution
When using immunoassay test strips for drug checking (as opposed to urine testing), sample preparation is important. Any drug can produce a false positive if over-concentrated, and if you don’t concentrate enough (over-diluting by adding too much water) you run a greater risk of false negatives.
The proper dilution for any drug checking strip is initially determined by laboratory analyses as well as relevant facts about the current status of the illicit drug supply, such as the average concentrations of various adulterants in specific drugs. Over time, field testing supplemented by confirmatory lab analysis (like GC-MS) may change our understanding of the optimum dilution.
As of right now, we have determined that the optimum dilution for using WHPM’s xylazine test strips to test powdered illicit opioids is two milligrams per milliliter (2 mg/mL). This is the equivalent of 10 mg of powder into one teaspoon (5 mL) of water, or one level micro scoop into a normal plastic bottle cap.
This concentration is capable of detecting even tiny, microgram levels of xylazine, and it should not produce false positives even if the sample contains high concentrations of fentanyl, heroin, diphenhydramine, alprazolam, diazepam, etizolam, oxycodone, hydrocodone, or lidocaine.
For testing M30 oxycodone pills and other pressed opioid tablets that contain binder material, crush and test:
- The entire pill in a quarter cup of water (four tablespoons)
- Half the pill in 1/8th of a cup of water (two tablespoons)
- A quarter of the pill in 1/16th of a cup of water (one tablespoon)
NOTE: We are in the process of producing printed instruction sheets for our xylazine strips. These will be ready to ship soon.
No xylazine strip on the market today has been assessed for efficacy when testing non-opioid drugs. Although the W.H.P.M. strips did not cross-react with methamphetamine and MDMA, they have not been tested with cocaine or other commonly used non-opioids. Furthermore, they did cross react with ketamine and levamisole, meaning they will definitely give false positives with ketamine (as well as cocaine if it contains enough levamisole).
Thankfully, as of the last time this article was updated (see the date at the top of this page) we have not been made aware of any ketamine samples found to contain xylazine, and when xylazine has appeared in other non-opioids like cocaine and meth, we’ve only ever seen it appear alongside fentanyl. Therefore, we do not advise testing non-opioids for xylazine at this time, especially given the possibility of false positives with ketamine and levamisole-containing cocaine. Testing with a fentanyl test strip should be sufficient and remains important.
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