Chart icon: chart user instructionsUsing our interactive charts

Drug checking in Washington state

Intake process

Drug checking is hosted at harm reduction service providers throughout the state. Samples are provided voluntarily by members of the community concerned about what might be in the drug supply. At intake, technicians fill out an electronic form in collaboration with the community member to describe what is being tested. This includes questions about what the sample was sold or given to the person as, what it looks like, and whether the drug in question has been consumed and, if so, observations and consequences.

The person requesting testing may provide a sample of the drug itself (a fraction of a pill or small amount of powder or tar) or they may offer residue in a pipe or cooker after use. Most of our analyses on these pages concentrate on testing samples of the drug itself before use, as testing pipes, etc., brings up issues of cross-contamination (finding what might have been in that pipe last week) and positive results for substances that appear after use (metabolites) or after exposure to heat or light (degradants). We cannot rule out all cross-contamination, however, because the container a community member uses might be used multiple times: We might still detect a substance that was in the baggy or tin earlier, but was not actually sold with the item the person wants tested.

Local testing

Drug checking sites have an array of test strips, which can give an often imperfect indication of whether the target substance (e.g., fentanyl) is present in the sample. Sites currently included in the data presented on these pages also have machines called Fourier-Transform Infrared spectroscopers that scan the samples and compare the results to known chemical signatures.

Confirmatory testing

To facilitate training and gaining of expertise, samples are currently sent for confirmatory testing. Detailed chemical analysis is done on each sample using mass spectrometry by our testing partner at the Opioid Data Lab at the University of North Carolina (UNC) or the National Institute of Standards and Technologies (NIST). Shipping, lab processing, and compilation of results creates a lag of at least two weeks, often longer.

Data structure

Intake information, including key variables such as test material (what was tested, generally divided into the drug itself before use or something holding residue from use), form (e.g., pill versus powder), and what the item was sold as, are recorded in one dataset with one row per submission. Confirmatory testing results arrive with one row per substance results. A given sample can have many substance results: Fentanyls, for example, often have multiple identified substances due to incomplete synthesis of fentanyl itself, so the results might indicate fentanyl specifically, one or more fentanyl analogues (e.g., para-fluorofentanyl), and one or more precursors (chemicals involved in the synthesis, which may or may not be psychoactive, such as 1-phenethyl-4-propionyloxypiperidine), in addition to any modifying agents (e.g., acetaminophen or xylazine) or bulking agents (e.g., sugars). In order to analyze sample results, these substances need to be coded to drug categories of interest and the data flattened to one row per submission.

Drug coding

Categorizing substance results to a useful taxonomy of drug categories is a difficult process, and inherently leaves out information in the interest of simplicity and summarizing. One person might be highly interested in the presence of 1-phenethyl-4-propionyloxypiperidine, others may simply wish to note the presence of all fentanyl precursors, and other may wish to simply include any psychoactive precursors in a broader fentanyl analogues category. ADAI has combined its experience coding and classifying similar testing results from state crime lab data with further input from chemical experts, drug checking sites, and people with lived experience to implement a categorization system used in these pages. This system combines codes that represent only one substance (e.g., fentanyl, cocaine, xylazine) and categories that group similar substances together (e.g., fentanyl analogues). Each category is then grouped into super-categories for purposes of summarizing the extent to which samples are testing positive for expected versus unexpected substances. These super-category labels--major, minor, other of interest, not of interest--have more to do with population-level health effects and in no way represent how you would feel if they showed up in your sample. Drug categories identified include: