Testing the Tests

DanceSafe is a nonprofit harm reduction organization that provides test kits and fentanyl test strips.  We've been working with them to evaluate some of the commercially available fentanyl test strips on the market.  Here is an example of early results from this collaboration.  

We compared three types of FTS.  In the top row are WHPM's Fen10 strips, lot F122221036, exp 2/28/25.  The middle row are BTNX 20ng/ml strips, lot DOA2204278, exp 04/11/2024.  The bottom row are BTNX 20ng/ml strips lot D805010, exp 05/12/20 (these strips expired in 2020 & were sitting unopened in a box in a harm reduction organization's storeroom).

The substances we tested are methadone (used to treat opioid addiction), lidocaine, levamisole, and procaine (all common cocaine cutting agents), and diphenhydramine (a common cutting agent in injectable opioids). Each substance was a pure compound dissolved at 10 mg/ml in DI water. 

In the photo below (click on the photo to enlarge it), two red lines should be read as a negative result, even if one of the line is a lot weaker than the other.  A single red line indicates that fentanyl is present. Since there wasn't any fentanyl in any of these solutions, the positive test results are all false positives.  


Screen Shot 2022 09 27 At 6
Fentanyl test strips with 10 mg/ml solutions of methadone, lidocaine, levamisole, procaine, and diphenhydramine.A green check mark indicates a clear negative result, a green check-minus shows a negative result where one line is very faint, and a red X means the result was a false positive.