About FentCheck® Fentanyl Test Strips

FentCheck® fentanyl test strips were developed explicitly for harm reduction use by W.H.P.M. With a detection cutoff of 10 ng/ml, they are the most sensitive test strips on the market. They are also highly selective to fentanyl and its analogs, meaning they are less likely to cross-react with other, non-fentanyl-related drugs.

The Importance of Sample Preparation

When fentanyl is contaminating other substances, it is unlikely to be mixed evenly. This is called the “chocolate chip cookie effect” and is why the best recommendation is to dilute and test the entire sample of the substance (i.e. pill or baggie of powder). However, because many people are only willing or able to test a small portion of their substance, sample preparation to avoid false negatives and false positives is extremely important. Here are the three components of proper sample preparation:

1. Crush and mix - In order to reduce the chocolate chip cookie effect and redistribute any fentanyl as evenly as possible throughout the sample, the entire sample must be crushed and mixed thoroughly.

2. Test as much as you are willing - To maximize the chance that the portion being tested will contain fentanyl (if fentanyl is contaminating the sample), test the largest amount possible. W.H.P.M. recommends a minimum of 50 mg.

3. Dilute the portion to 10 mg/ml* - To maximize the chance of detecting even a tiny amount of fentanyl that was hopefully captured in the chosen portion, dilute the portion only enough to avoid false positives, and not much more. The FentCheck® fentanyl test strips have been laboratory tested on the most common drugs and drug cuts, and they did not produce false positives even at the high concentration of 10 mg/ml in water.

Following the protocols for sample preparation above are the best practices for using the FentCheck® fentanyl test strips.

The following User Instructions were specifically developed by W.H.P.M. (the manufacturer of the test strips) to optimize the performance of the FentCheck® fentanyl test strips to ensure accurate detection while limiting the possibility of cross-reactivity.