At the overdose prevention site in Moss Park, harm reduction workers will soon have another tool to help drug users avoid fatal overdoses — test strips able to detect the presence of fentanyl.

Zoe Dodd, who volunteers at the site, says someone is donating test strips to the site and they'll be used as soon as they arrive.

"We have a toxic drug supply," Dodd told CBC Radio's Here and Now.

At the same time, she said, "we know that people will not stop taking drugs."

While many drug users may still take fentanyl-laced products, even after a positive test, there's hope that knowing that the powerful opioid is mixed in with their drugs may prompt them to use more cautiously, or at one of two supervised injection sites now operating in the city.

Dodd says the tests will also give harm reduction workers a clearer picture of what drugs are going around, allowing them to provide more warnings to users.

Harm reduction workers in Vancouver, where some 232 people have died after overdosing in 2017 — surpassing last year's total — have already been using the strips.

Toronto Public Health, however, isn't using the test strips at its supervised injection site at this time, a spokesperson confirmed in an email. On its first day, seven people used the facility.

Markham company behind tests

BTNX, a Markham-based biotechnology company, makes the test strips, which look a lot like pregnancy tests.

CEO Iqbal Sunderani told Radio-Canada the tests were originally intended for doctors, so they could ensure their patients were taking their prescribed pain medication by testing their urine. That changed when the opioid crisis worsened and there was more demand to test drugs themselves for fentanyl, by dissolving a small amount of it into a solution.

Harm reduction workers were some of the first people asking for it, Sunderani said.

"They can use it to meet the challenge of this epidemic, to see if they can save lives," he said.

Test can produce false negatives

The test isn't perfect and can produce false negatives — "that's a big concern to us," Sunderani said — but it is sensitive enough to detect many fentanyl analogs, including carfentantil.

Nazlee Maghsoudi, of the International Centre for Science in Drug Policy, said while there are more advanced ways of testing drugs out there, the strips offer a fast method that does work in the real world.

"They are quite important," she said.

With files from Radio-Canada and Here and Now