What does a negative result on a home COVID-19 test really mean?
This is the question that has confused many people who have arrived for the test at home because they have a sore throat, cough or runny nose. After pricking their nose and waiting anxiously for 15 minutes, the result is negative.
While there is relief in getting negative results, there is also uncertainty. Am I really free from COVID? Or did the test not detect it? Should I test again? Can I spend time with other people?
Testing and public health experts say the confusion is justified. This stems from a lack of understanding of how tests work. Rapid home antigen tests look for fragments of viral proteins from a swab of your nose, and they are designed to identify whether you have an infectious level of the virus. But a negative test does not guarantee that you do not have COVID.
It could be that your symptoms are an immune response indicating the arrival of COVID or another invader. The harder your immune system is working to reduce the virus, especially the immune system supercharged by vaccine antibodies, the more likely you are to get an initial negative result on a rapid test, even if you get infected
“Maybe the virus in your body is tug of war with your immune system,” said Dr. Michael Minas, chief science officer for eMed, a company that helps rapid test users receive treatment from home. “If you test negative and you have symptoms, don’t assume you’re negative. Don’t assume the virus hasn’t had the opportunity to multiply yet. Symptoms may mean your immune system is too early warning giving.”
Meena advises people to get a rapid test done on the first day of symptoms. A positive result means you almost certainly have COVID. If the result is negative and your symptoms continue, you should still take precautions, wear a mask, and avoid close contact with other people. If you cannot test daily, wait 48 hours and test again. If you are still negative, but your symptoms persist or get worse, you should have another test on day 4. Or you may want to go to a testing center to have a PCR test, which can sometimes detect COVID a little sooner. Home test, though you may have to wait a day or two for the results.
Experts say that if you have symptoms and keep getting negative results on home tests, your immune system may be doing a good job defeating the virus. Or maybe you have some other disease. Either way, you should try to avoid infecting others.
“If you have symptoms and continue to test negative, the chances that you are contagious with COVID have greatly reduced,” he said. Dr. Robert Wachter, chair of the Department of Medicine at the University of California, San Francisco. “But you should probably wear a mask that day because you have some.”
And, remember, the result of your home test is information only. If you haven’t left the house in weeks, your negative result will probably be accurate after a few tests. If you have symptoms and are spending time at bars or a family member has been exposed to COVID, you should be more vigilant, even if initial results are negative. You may have tested too early and your viral load is not high enough to be detected.
When Dr. Jillian Horton, an internal medicine doctor in Winnipeg, Manitoba, began to feel ill, she was pretty sure she had COVID. Her husband was exposed and he had symptoms too. He decided to conduct an experiment, testing himself several times over the course of a few days to track the dynamics of the virus. “With my husband testing positive and being very symptomatic in himself, I was sure I had COVID,” Horton said. “I was curious to see what I could point to when I could flip positively.”
Horton’s husband became ill Friday night, and that evening he tested negative. On Saturday, she started feeling ill and took her test thrice a day. The results of all three were negative.
By Sunday morning, she woke up and her health was deteriorating. At 6 a.m. she took the test and saw a faint line on the test – which she called a “weak positive.” He took two more tests on Sunday, and both were negative.
On Monday morning, he tested again, and the test rapidly turned out to be positive.
What’s remarkable about Horton’s experiment is that if he had tested at a different time on Sunday, he might never have detected the weak positivity. Her immune system was clearly battling the virus, as evidenced by her two negative test results earlier in the day.
Horton said testing at the right time to catch a high viral load was akin to casting a net in a stream. If there are no fish, you won’t be able to catch anything. But if you time it so that the fish are plentiful, you’ll catch your dinner.
Horton said she was concerned that many people think the tests aren’t working when, in fact, they’re a useful tool if you understand how to use them. They are ideal for “ruling” COVID, but you need to consider more details when evaluating a negative test.
“Often I hear people say, ‘Tests suck,'” Horton said. “What my experience showed is that when you have symptoms, the tests are really ‘rule-in’ tests. I think back to the two days when I was so symptomatic. I had a positive test and There were five negative tests. There was only one moment where I was more infectious.”
Linsey Marr, a professor of civil and environmental engineering at Virginia Tech and one of the world’s leading experts on viral transmission, said she believed her daughter had COVID even after a rapid test came back negative. The child had fever and sore throat, and was exposed to COVID through her gymnastics team.
But the test proved useful for knowing that her daughter was not highly contagious, helping Marr’s family learn how to manage the risk. “We knew we needed to be careful,” Mara said. “But we didn’t have to jail him completely. The test told us that the viral load was not high enough that we had to lock her in her room and we all had to worry about getting it. Instead, the family wore masks and opened the windows to improve ventilation.
Christina Kasparian, who works from home in Montreal, believes she may have got COVID from her husband, who is a schoolteacher. They disagreed as to whether a home test taken by them found a faint positive. But a few days later she woke up with tightness in her chest and a sore throat. Her test was positive, and her husband continues to test negative.
“It’s great to have this tool, but it’s such a variable snapshot over time,” she said.
Meena said that despite the limitations, people would benefit from frequent testing any time they suspect they have been exposed, have symptoms or want to make sure they are not contagious before spending time with a high-risk person. Huh. He also recommends testing before you start interacting with others again, to make sure you still aren’t contagious.
“These are tools that have massive benefits during a pandemic like this,” Meena said. “They’ll catch you when you’re most contagious. Even when you’re slightly contagious, they’ll catch you most of the time. They’ll catch almost everyone when they have enough viral load to spread. But get it right Will not done.”
This article originally appeared in the new York Times,