As Canada’s supply of street drugs grows increasingly dangerous due to harmful additives, testing kits have offered a glimmer of hope for drug users and those working to help them.
But on Monday, Health Canada warned that illicit drug test strips might not detect dangerous substances, including xylazine and fentanyl.
“No test is 100 per cent effective at detecting all potentially dangerous substances in illegal drugs,” Health Canada said in a statement.
“A false negative could result in a fatal overdose. Treat all illegal drugs as though they are potentially contaminated with unknown and dangerous substances.”
The agency warns that such test strips may be sold online or in stores as consumer products, but are not reviewed by the federal government for evidence of effectiveness as is done for medical devices.
A false negative means the test did not detect the targeted drug even though it was present in the sample. The agency says such a result can lead to a false sense of security.
Test strips work by mixing a sample of a substance with water and dropping the mixture on the strip.
Since 2016, more than 30,000 people have died of an overdose in Canada, according to Mental Health and Addictions Minister Carolyn Bennett, with the country seeing “substantially elevated numbers of opioid-related deaths and other harms.”
“According to recent national data, there were approximately 20 opioid-related deaths per day from January to September 2022,” she said recently during an event in London, Ont.
Those working day in and out to save the lives of drug users say the test kits have become a popular tool.
“We’ve been seeing people dropping like flies, people that normally know their doses of substances,” Shannon Hart, an Alberta harm reduction expert, told Global News earlier this month. “But because of these harmful adulterants being introduced, it’s creating more overdose and destruction in the community.”
Hart hands out whatever tests she can get her hands on.
“The demand — we can’t get enough strips.”
Drug supply and testing researchers Global News spoke with say they understand why Health Canada would take a cautious approach toward test strip usage, but argue the testing kits are better than nothing.
Daniel Werb, an associate health policy professor at the University of Toronto, told Global News test strips are most commonly used to detect fentanyl, with an accuracy of finding a presence of less than five per cent, which he said is enough to prove fatal.
Werb, who is involved in commercializing a new drug testing technology, said that’s a higher level of detection than infrared spectrometry technologies that clinics use to test drugs, which can detect a broader range of drugs present but not a presence below five per cent.
“The whole idea around fentanyl test strips is that they’re able to detect fentanyl when it’s present at very low concentrations,” he said.
Health Canada said test strips may not detect other lethal drugs as harder street drugs are entering Canada’s supply.
The animal tranquillizer xylazine is now becoming more available in Canada after wreaking havoc in parts of the U.S. Ninety per cent of opioid samples in Philadelphia in 2021 had xylazine, according to data released by Substance Use Philadelphia. It is being mixed in with fentanyl and many users don’t know it’s there.
“Our understanding was that most folks in Toronto were not choosing to use xylazine, it was just kind of being cut into their drugs unknowingly. So it certainly is a problem,” Karen McDonald, the lead for Toronto’s Drug Checking Service, told Global News in an earlier interview.
Repeated xylazine exposure can cause significant harm. It does not respond to naloxone — a medication that can reverse the effects of opiates — and makes overdoses from opioids mixed with this sedative more challenging to treat.
Carfentanil is another drug entering Canada’s supply that is up to 100 times stronger than fentanyl and may evade test detection, Health Canada warns.
Sam Tobias, a research assistant at the University of British Columbia specializing in drug supply, told Global News testing strips are becoming more widely available in B.C., but they have limitations.
For example, illegal drugs may be mixed in unevenly with other substances, leading to test evasion.
He recommends using both a test strip and the higher-end machine at testing centres to get a comprehensive view of what is in a drug.
Health Canada says it is working with companies to include warnings on the packages of test strips to better inform consumers of the risks of unreliable results.
“It’s really important that people understand what (the test’s limitations) are,” Tobias said.
“Then take those limitations and sort of interpret what the results mean in the context of those limitations.”
— with files from Teresa Wright, Amy Simon and Adam Toy.
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