What's in 958 samples sold as fentanyl?

How often are drug types found together in confirmed drug checking results?

A given drug sample can have multiple positive results for different drugs. One way to examine these results is to look at how often things are detected together. In the heatmaps below, we present the percentage of samples testing positive for the pair of drugs or drug categories listed. This comparison of the co-presence of two drugs cannot account for the fact that there are often three or more drugs present. The diagonal (where the column name and row name are the same) represents those samples testing positive for only that drug category (these samples may have tested positive for a drug category not listed here). The rows and columns are ordered from largest to smallest share of drug checking samples, alone or in combination. For more details on drug categories named, click here.

“Fentanyl” is a particularly complicated drug category as it almost always has other related compounds present due to manufacturing processes. For example, if you mouse over the row marked Fentanyl analogues and the column marked Fentanyl, you can see that 12% of these samples involved fentanyl and at least one fentanyl analogue, with or without any other drug mentioned here or any drug not included in the matrix.

If you mouse over the Fentanyl alone cell (Fentanyl row and Fentanyl column), you can see that 27% tested positive for fentanyl and no other category here. If you move along the Fentanyl row (or column) you can see the share of all samples that tested positive for fentanyl itself and that other drug type. If you move along the Xylazine row or column, you can see that 99 of the 102 fentanyl cases positive for xylazine also had fentanyl, 36 had fentanyl analogues, 1 a novel synthetic opioid, 15 methamphetamine, and 2 cocaine. The Fentanyl analogues alone cell indicates that 12 samples sold as fentanyl contained no fentanyl itself but did contain one or more analogues and nothing else presented in the matrix. (Around 2.8% of samples submitted as "fentanyl" have fentanyl analogues but not fentanyl itself. This rate increased during the summer and early fall of 2024.) Similarly, 72 samples had other analgesics (often acetaminophen) and no other drug category presented here, 9 had meth alone, 7 had cocaine alone, and one ketamine alone. Fourteen samples contained no drug presented in the matrix.

Data notes

Drug testing sites can do little about potential cross-contamination: The container a client used may or may not have been used before. Therefore, any unusual combination may be due to cross-contamination and not represent drugs actually sold together. Results are cumulative and reflect all confirmatory testing results as of 12:15PM PST 17 December 2024.

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