Vancouver Coastal Health (VCH) is going to start offering its drug-checking service — which allows users to test their drugs for fentanyl and carfentanil — at more locations across the city.

The system, which is free, was previously only available at Insite. On Thursday, the authority announced it will now be offered at the city's four overdose prevention sites, as well as the Powell Street Getaway supervised injection service.

VCH launched the pilot project on July 7, 2016. In the first year of operation, more than 1,400 checks were done — 80 per cent of which came back positive for fentanyl.

Health officials are adding more sites where people can test drugs for fentanyl. Tests strips can also now detect carfentanil. <a href="https://twitter.com/hashtag/yvr?src=hash">#yvr</a> <a href="https://t.co/SKrXsB98ou">pic.twitter.com/SKrXsB98ou</a> —@briarstewart

A statement said Insite clients who got a positive result were 10 times more likely to reduce their dose. Those who did so were 25 per cent less likely to overdose.

To use the checking system, clients use a test strip — originally designed for urine testing — to dilute their drugs with water. After a few seconds, a positive or negative reading for fentanyl appears.

The authority said it recently discovered the method can also detect other potentially deadly opiates, including carfentanil.

In the first six months of 2017, about 780 people in B.C. died of an overdose. (Tina Lovgreen/CBC)

Last week, the City of Vancouver said more people have died of a drug overdose so far in 2017 than during all of 2016.

As of Aug. 21, the total number of overdose deaths in the city was estimated to be 232. Many involved fentanyl.

Mental Health and Addictions Minister Judy Darcy said the Vancouver numbers show "there are gaps in services." Vancouver Mayor Gregor Robertson called the statistics "heartbreaking."

The B.C. Coroners Service said 780 people died of a drug overdose across the province in the first six months of the year— an 88 per cent increase from the same period in 2016.

With files from Briar Stewart