When Dr. Jillian Horton, an internal medicine physician in Winnipeg, started feeling sick, she was pretty sure she had Covid. Her husband had been exposed and also had symptoms. She decided to conduct an experiment of one and test herself several times over the course of a few days to monitor the dynamics of the virus. “With my husband testing positive and myself being very symptomatic, I was sure I had Covid,” said Dr. Horton. “I was curious to see what I could pinpoint in terms of when I might flip positive.”
Dr. Horton’s husband became ill on a Friday evening and she tested negative that evening. On Saturday she started to feel sick and tested herself three times during the day. All three results were negative.
She woke up Sunday morning and felt worse. At 6 a.m., she tested and saw a faint line on the test – what she called a “weak positive.” She took two more tests on Sunday and both were negative.
She tested again on Monday morning and the test quickly turned positive.
What’s striking about Dr. Horton’s experiment is that if she had tested at any other time on Sunday, she might never have discovered the faint positive. Her immune system was clearly fighting the virus, as evidenced by her two negative test results later in the day.
dr. Horton noted that testing at the right time to catch a high viral load was akin to placing a net in a stream. If the fish aren’t there, you won’t catch anything. But if you time it so the fish is plentiful, you’ll catch your dinner.
dr. Horton said she was concerned that too many people think the tests don’t work, when in fact they are a useful tool if you understand how to use them. They are ideal for ‘closing in’ Covid, but you need to consider more information when evaluating a negative test.
“So many times I hear people say, ‘The test is useless,'” said Dr. Horton. “What my experience illustrated is that when you have symptoms, the tests are really ‘rule-in’ tests. I think of those two days when I was so symptomatic. I had one positive test and five negative tests. There was only one moment when I was more contagious.”