Testing has been one of the key mantras among public health officials in Ontario and throughout the country since the COVID-19 pandemic began and one which has been echoed by the mainstream media for just as long.

“Testing is the key,” they all said. “We need to get people tested, so we can do the necessary contact tracing.” “We need to test everyone coming into the country.” And my favourite: “We need testing to keep people safe.” The problem is that sometimes it can do the exact opposite. In fact, an argument can be made that flawed testing may have cost people their lives and I’ll explain why.

Early on in the pandemic, a friend of mine who is a research scientist here in Ontario, told me that testing was a waste of time. My friend cited that if you test negative one day you may still catch the virus the next day.

Now we find out through various reports that if you test negative you may still, actually, be positive. “Testing,” my friend said, “was for the data collection people and statisticians.”

I thought about what she said when Ottawa Public Health sent out the mixed messaging regarding testing. On the one hand, they advised people to remain at home if they started to exhibit COVID-19 symptoms, but then in the same breath they recommended that people with symptoms should get tested. Which is it?

Another red flag moment came when the Canadian government started insisting that anyone arriving in Canada from abroad must be quarantined in a hotel at their own expense while they get tested, even though it was already necessary for people to have a negative test no more than 72 hours before returning to Canada.

Could it be they didn’t trust the testing being done in some foreign countries? And if they didn’t trust the testing, why not?

There has always been the potential for false negative results, but there is also the potential for false positive results.

A false negative result is problematic for obvious reasons. If someone falsely tests negative for COVID-19 when in actual fact they have the virus, they can cause quite a lot of damage by unwittingly passing it on to others. It’s one of the reasons that I have been arguing for double testing for months. Back-to-back tests, three to four days apart, is standard for most front line health care workers. The idea being that the second test will catch the false negative of the first test.

But what if the first test was right and the second test was wrong? Could there be a potential for a false positive result? More so than you think and that’s because of the way COVID testing is conducted.

When a person goes for a test, a nasal swab is taking using what is essentially an over-sized Q-tip. The swab is then sealed and sent to a testing facility where it is tested not once, not twice, not 12 times, but possibly 45 times as the lab technicians try to find the existence of the COVID-19 virus in the sample.

BACK TO THE BEGINNING

Each of us reacts totally differently to the COVID-19 virus and our reaction is based on two factors – the strength of our individual immune system and the level of virus we have been exposed to known as the “viral load”. Your viral load is a combination of the level of virus you’ve been exposed to and the duration you were exposed to it.
Your viral load also changes over the course of your infection. It’s highest four or five days after you’ve contracted the disease and goes down from there.

After a certain a amount of time, your viral load is not sufficient enough to infect others, and in fact, remnants of the virus can stay in your system for months, which is where the issue of false positive results comes into play.

Getting back to the testing. The standard test to detect COVID-19 is called a Poly-merase Chain Reaction test, or PCR test, which dramatically amplifies the amount of genetic material captured in a sample and then compares it to the DNA or RNA of a particular segment of the COVID-19 virus.

If the virus isn’t detected in the initial test attempt, the PCR process increases the genetic material present by copying it and then copying it again, over and over until the virus is eventually detected. Each time the material is replicated is referred to as a “cycle” and the total number of cycles is referred to as a cycle threshold, or Ct.
If someone has a heavy viral load, the virus will be detected within the first few cycles. The smaller the viral load, the more cycles that are needed to detect it.

HOW TESTING CAN BE PROBLEMATIC

There are two different ways to conduct PCR testing – qualitative and quantitative.
So how does a qualitative PCR test work? Basically, the manufacturer sets the test to turn off the cycling or amplification process after a pre-determined number of cycles. If a qualitative is set at 40 cycles, it will turn off after the 40th cycle whether the virus was detected during the 25th cycle, or the 30th cycle, or whenever.

A quantitative test is designed to come up with the actual cycle threshold value as the cycling process turns off when detecting any virus. There is not a preset value, so a quantitative measure is obtained. A test that registers a positive result after 12 rounds of amplification for a Ct value of 12 starts out with 10 million times as much viral genetic material as a sample with a Ct value of 35.

So now we begin to see the problem.

Some labs can put a sample through 40-45 cycles before any trace of the virus is eventually detected. But here’s the kicker – no matter how many cycles if takes to detect the virus, the person infected is still referred to as an active case.

This is problematic for a number of reasons. It gives a false sense of the number of asymptomatic people that are in the community as health officials automatically assume that a positive test result from a person not showing symptoms is therefore asymptomatic; and it can falsely indicate that someone who has already had the virus still has it and can therefore be listed as an active positive case when in actual fact the result is a remnant of the virus.

According to the Journal of Clinical Virology, labs in Ontario set there testing equipment to cut off anywhere from 38 to 45 cycles.

The Centre for Disease Control in the United States recommends that the tests should cut off at 33 cycles to eliminate the chance for positive results from samples that are non-infectious because the viral load is too small, or from samples that are merely remnants of the virus.

The latter is more prevalent than you would think, owing to the fact that people with a strong immune system will only experience mild or moderate symptoms and therefore not subject themselves to testing at the time. If those same people go through a PCR test for whatever reason later on down the road, they will inevitably test positive even though they are no longer infectious. Weeding them out would require an anti-body test.

Most virologists now believe that the PCR tests should cut off after 30 cycles.
Counting positive results from tests that are run at 30-45 cycles gives an inaccurate indication of the number of active cases on any given day as well as an overblown positivity rate.

Incredibly, testing facilities are not obli-gated to give the Ct values to public health agencies and in most cases the public health officials aren’t interested in them. Even more incredibly the person being tested isn’t privy to that information either.

So why is that? The only possible reason is that it doesn’t fit into the public health narrative which is to keep people at home to prevent the spread of the virus.

But there’s no question that using Ct values over 35 means the current number of active cases, new cases and asymptomatic cases are overinflated.

In a perfect world, Ottawa Public Health would report the Ct values among the active cases. For instance, out of 1,000 active cases 70 per cent were the result of tests under 30 Ct and 30 per cent were from tests over 30 Ct. That would give us a better picture of the potential for transmission.

REAL WORLD ISSUES

We’ve already established that qualitative PCR COVID-19 tests give a false impression of both the number of active cases in the community and the improbability on unlikelihood for people to be infectious whose samples were subjected to a high Ct value.

So how can this potentially affect you? Well, your reaction to a positive test might be different if you found that it took 40 cycles to detect the virus in your system.
There is a direct correlation between viral load and the Ct value. The lower the Ct value the higher the viral load and vice versa.

At present, you merely have to test posi-tive to be subjected to a 14-day quarantine period. But if you were to test positive and found out that it was the result of a 35-45 Ct value, there would be no need to quarantine.

If laboratories were directed to set their testing equipment to 30-35 cycles, it would give us a clearer picture of the actual number of infectious cases that are out there rather than a global figure.

In the final analysis, there’s no question that the reporting of test results in terms of the number of active cases at any one time is flawed. If political leaders and public health officials are going to use testing and data to establish public policy they should be telling Canadians the whole story. In the meantime, hospitalizations are still the truest barometer by which the seriousness of the pandemic can be measured at any given moment.