South Korea has been hailed around the world for its vast amount of Covid-19 testing, conducting 20,000 tests per day at the recent height of efforts to fight the disease.

But Canada’s westernmost province of British Columbia is now exceeding that peak daily rate on a per capita basis by a wide margin of about 75 per cent.

On the same measure, BC is testing at more than triple the rate of the rest of Canada – and more than five times the daily rate in the US over the past week, even as Canada’s southern neighbour embarks on a huge escalation of testing efforts.

British Columbia’s health minister, Adrian Dix, announced on Tuesday that the province was conducting 3,500 tests per day.

That equates to 690 tests per million people, daily. By comparison, South Korea’s peak daily testing rate amounted to about 392 tests per million. BC has a population of 5.1 million, while South Korea has 51 million people.

“Thirty-five hundred tests is what we’re doing every day, which is an extraordinary increase,” Dix said, hailing the work of the BC Centre for Disease Control. It is only two weeks ago that BC’s testing capacity was about 800 per day.

LifeLabs and other private facilities were part of the effort to ramp up testing, Dix said.

British Columbia is currently the most-infected province in Canada, with 617 confirmed cases, although it is likely to be soon surpassed by Quebec, which has a large number of presumed cases. BC accounts for 13 of Canada’s 27 known Covid-19 deaths.

All British Columbians have been told to stay at home to prevent the spread of the disease and to maintain at least 2 metres of distance from others when outside their homes.

Authorities in BC have come under criticism for supposedly inadequate testing, the fact that not all travellers are tested for the disease, and that even suspected cases are not always tested.

But provincial medical officer Dr Bonnie Henry said that failing to test travellers who exhibited symptoms of Covid-19 was not an oversight, but part of a deliberate strategy.

“To be clear: we are absolutely testing and contact tracing anybody for whom we don’t know the source of their infection,” she said. “We know the source of infection for people who are coming in from outside Canada.”

Since an order was already in place that all people arriving in BC from overseas must self-isolate for 14 days, there was no need to test those people if they showed symptoms, said Henry, since it was assumed they had the disease anyway.

“We don’t need them to go out of their house to go some place to be tested, maybe exposing other people. We assume that they have this disease, we manage them accordingly, and we make sure they don’t have contacts that pass it on to others.

“That’s how we break those chains of transmission, which allows us to focus on the community cases of transmission for which we do not know the source of infection.”

Henry said on Tuesday that BC had conducted about 30,000 tests; a day earlier, BC had reported 26,861 tests, and a three days before that 17,912, putting the province on track for Dix’s estimate.

By comparison Canada is doing 10,000 tests daily, according to chief medical health officer Theresa Tam. Excluding BC, that amounts to about 200 daily tests per million.

Meanwhile, the United States has also been dramatically escalating testing. According to the Covid Tracking Project, which compiles state-based American data, the US has conducted 304,204 tests over the past week – an average daily rate of 133 per million people.

Although massive testing was crucial in arresting the outbreak in South Korea, its circumstances are specific – of the 357,000 tests conducted there as of Tuesday, about 60 per cent were for members of a religious sect at the centre of an outbreak that constituted the bulk of all infections in the country. Testing at the peak rate of 20,000 per day was being conducted largely off a list of 212,000 church members.

But mass testing on those worshippers has now been completed, and for the past week, South Korea has averaged 8,892 tests a day, or 174 daily tests per million people.

Cumulatively, BC’s approximately 30,000 tests amount to about 5,900 tests per million people; all of Canada’s 125,062 tests amount to 3,326 per million; and the US’ 367,710 tests amount to 1,124 per million.

Testing varies widely in the US, with New York state, which has the most cases, having conducted an average of 12,000 tests a day over the past week at a rate of 612 per million, daily. Governor Andrew Cuomo said on Tuesday that the state was conducting 16,000 tests a day.

South Korea’s 357,000 tests, meanwhile, represent about 7,125 tests per million people.

The World Health Organisation has urged nations to “test, test, test” all suspected cases of Covid-19.

But Henry said BC’s approach represented the best way to target the disease, with health workers, for instance, being “aggressively” tested.

“When we talk about ‘test, test, test’ the focus is on making sure we know where new cases are coming up where we don’t have a known source,” she said.