Testing street drugs for fentanyl: Does it reduce overdoses?
A pilot project by Insite that allows drug users to check their drugs for the presence of fentanyl has received a lot of publicity. Now, according to this article in the Globe & Mail, the BC government is going to increase the availability of these tests:
British Columbia is set to expand a program to allow people to check their street drugs for fentanyl, the latest harm-reduction initiative to roll out amid skyrocketing overdose deaths.
The most recent figures from the provincial government show 1,103 confirmed deaths from overdoses of illicit drugs in the first nine months of this year. The year-end total is on pace to be around seven times the annual average in the 2000s.
I’m going to take a few moments to explain why this harm-reduction strategy, in its current form, is a bad idea.
First, it is likely that cross-contamination is causing false positives. Insite is not a sterile lab environment, and nor are the drug users who are conducting these tests. Trace amounts of fentanyl and other opiates are likely present on their hands, clothes, etc. Only a very small amount of fentanyl is required to generate a positive test result.
Street drugs are often cut with a buffer, and the result is not a uniform mixture. For example, low-grade heroin cut with fentanyl has not been mixed to pharmaceutical standards. A tiny sample tested at Insite might have no fentanyl, but there could still be enough fentanyl in the remaining dose to kill the user. Also, the tests used by Insite result in false negatives. It’s also worth noting the tests can detect fentanyl, but may not be able to accurately or reliably detect other synthetic drugs such as W-18. The latter is known to be present in British Columbia. W-18 is orders of magnitude more toxic than fentanyl.
As mentioned the test itself, even if used correctly, inherently has a false negative rate. This means the test will sometimes come back negative even through fentanyl is present. Furthermore, the drug test strips were only designed to be used for human urine samples as a preliminary test. I obtained a copy of the BTNX Single Drug Test Strip from Kwan Tse, manager of QA / RA at BTNX Inc. Excerpts from this product insert include numerous warnings (emphasis added by me).
In the section labeled INTENDED USE:
The Rapid Response Single Drug Test Strip is rapid chromatographic immunoassays for the qualitative and simultaneous detection of one of the following drugs in a variety of combinations in human urine.
This assay provides only a preliminary analytical test result. A more specific alternative chemical method must be used in order to obtain a confirmed analytical result.
In the section labeled QUALITY CONTROL:
Good laboratory practice recommends the use of control materials to ensure proper kit performance. Quality control specimens are available from commercial sources and are recommended to be used daily. Use the same assay procedure as with a urine specimen. Controls should be challenging to the assay cutoff concentration. If control values do not fall within established limits, assay results are invalid. Users should follow the appropriate federal, state, and local guidelines concerning the running of external quality controls.
There is no indication from Insite that control materials were used on a daily basis to ensure the validity of their off-label fentanyl screening tests. As such their test results are unreliable.
In the section labeled LIMITATIONS OF THE TEST:
The assay is designed for use with human urine only.
There is a possibility that technical or procedural error as well other substances as factors not listed may interfere with the test and cause false results. See SPECIFICITY for lists of substances that will produce either positive results, or that do not interfere with test performance.
In the section labeled Specificity:
The Specificity for the Rapid Response Single Drug Test Strip has been tested by adding various drugs, drug metabolites, and other compounds that are likely to be present in drug-free normal human urine. The Rapid Response Single Drug Test Strip performance at cutoff point are not affected when pH range of urine specimens is at 3.0 to 8.5 and specific gravity range of urine specimens is at near 1.005 to 1.03.
The specificity testing for this product was limited as the company was only considering what was likely to be found in drug-free human urine. It should be obvious by now that this product was never designed to be used for the testing of unknown street drugs prior to their consumption by humans.
The pilot project results obtained by Insite are compromised by these limitations. It is likely that various adulterants in street drugs as well as the drugs themselves are causing either false positives or false negatives.
There is also a risk that Insite is simply confirming the presence of fentanyl for drug traffickers whose true intention is to sell fentanyl on the streets. The data from the pilot project hints at this. Here is an excerpt from the abstract presented at the 2017 Harm Reduction International conference:
Of substances checked pre-consumption, compared to receiving a negative result, receiving a positive result did result in more dose reductions (37% vs. 8%) but not in more disposals (9% vs. 8%).
And so even when street drugs tested positive for fentanyl, the users did not get rid of their drugs. The users said (to Insite staff) that they were reducing their planned dose, but there was no way to verify the truth of those statements. What the data shows is that clients walked out of Insite with their fentanyl-laced dope. Their likely plan was to sell their fentanyl to unsuspecting users, or to keep it for themselves and use it on their own. Both choices have almost certainly resulted in fatal consequences for people who use drugs in British Columbia.
I have been a public advocate of harm reduction for almost a decade. But harm reduction supporters should not blindly accept every strategy and method put forward as harm reduction. Because the Insite pilot project did not result in users getting rid of their fentanyl, it cannot be said that testing street drugs for fentanyl actually reduces overdoses.
One last point: The data showing that users did not dispose of their fentanyl-laced drugs (once they become aware of the contamination) was never included in the original media release by Vancouver Coastal Health. I think it was an important point for journalists to know. Particularly as that media release generated worldwide coverage. Users and user-dealers were walking out the doors of Insite into the broader community, believing that the dope in their possession was fentanyl. It should have been in the original media release.
Disclaimer: The opinions expressed in this blog post represent my own personal views, and not those of my employer (or any other organization).