Publicly funded COVID-19 tests in B.C. come back positive more often, data shows
A technician prepares COVID-19 coronavirus patient samples for testing at a laboratory in New York's Long Island on Wednesday, March 11, 2020. (AP / John Minchillo)
VANCOUVER -- As COVID-19 cases in B.C. have surged, so has the percentage of tests for the coronavirus that are coming back positive.
While this correlation is not surprising, a change to the way the provincial government reports testing data helps to highlight just how dramatic the increase in the rate of positive tests has been.
During her latest update on the pandemic Friday, provincial health officer Dr. Bonnie Henry announced that the province would now be reporting two different types of test-positivity rates.
The first rate, which has been reported since the start of the pandemic, reflects all tests conducted in the province, regardless of whether they're conducted through the public health-care system or through some other agency, such as the federal government or a private business.
The second rate, which was first published in the B.C. Centre for Disease Control's latest COVID-19 situation report on Friday, reflects only tests conducted in the public system.
"As our cases and our surge has increased here in B.C., we've seen a difference in the per cent (of) positive (cases) between these two testing groups," Henry said Friday.
The two groups of tests, which Henry referred to as "MSP" and "non-MSP" based on whether they're paid for by the province's Medical Service Plan, tend to be conducted for very different reasons, the provincial health officer said.
The province's testing strategy remains focused on case identification and contact tracing, while non-MSP tests tend to cast a wider net, Henry said.
"The (private) non-MSP tests include mostly people who are asymptomatic," she said. "Often, they are people who are being tested multiple times for work or for travel."
The difference in positivity rates between the two groups has been "considerable" over the last few weeks, Henry said.
According to the BCCDC's report, more than 80,000 total tests were conducted in B.C. this week. A total of 6.6 per cent of those came back positive, a significant increase from the 1.4 per cent positivity rate B.C. was seeing just six weeks ago.
Among only MSP-funded tests, however, the positivity rate grew even more sharply. Six weeks ago, the MSP group had a positivity rate of 1.8 per cent. This week, 8.5 per cent of those tests came back positive.
As might be expected, given that the vast majority of B.C.'s COVID-19 cases have been located in the Lower Mainland, Fraser Health and Vancouver Coastal Health have the highest rates of positive tests.
Nine per cent of all tests conducted in the Fraser Health region this week were positive, a figure that rises to 11.2 per cent when looking only at the MSP tests.
In Vancouver Coastal Health, 4.8 per cent of all tests conducted were positive, but 7.9 per cent of MSP-funded tests had positive results.
In other health authorities across the province, non-MSP tests make up a smaller proportion of the number of tests being done, overall. Thus, there is less variation between the MSP-only and overall positivity rates, according to the BCCDC.
Northern Health had the highest positivity rate outside the Lower Mainland this week, with 7.8 per cent of all tests coming back positive. In Interior Health, 4.6 per cent of tests were positive, while 1.5 per cent were positive in Island Health.