All Your Questions About At-Home COVID Tests, Answered
It's been nearly four years since people started getting sick with COVID-19, but with new variants mutating each season, the health steps experts asked us to take at the beginning of the pandemic still hold true: If you develop symptoms of the virus, test yourself at home, and then, if the test is positive, follow medical guidance regarding quarantine.
But a lot has changed since the the early days of the pandemic, so it’s understandable to wonder whether at-home COVID tests are still accurate, especially with all of the variants that have come and gone. The latest variant to dominate in the U.S. is JN.1, which now is responsible for nearly 62 percent of COVID cases in the country, per data from the Centers for Disease Control and Prevention (CDC).
So, how accurate are at-home COVID tests now, how likely are false negatives, and when should you test yourself? Below, two infectious disease doctors break it all down, and answer your most pressing at-home test questions.
Meet the experts: Thomas Russo, MD, is a professor and chief of infectious diseases at the University at Buffalo in New York. William Schaffner, MD, is an infectious disease specialist and professor at the Vanderbilt University School of Medicine.
How reliable are at-home COVID tests?
COVID tests can generally be divided into two camps: Rapid antigen tests and polymerase chain reaction (PCR) tests. Rapid tests are those tests you can do at home and provide results in about 15 minutes. On the other hand, you usually need to have a PCR test administered at a medical facility, and there's a longer turnaround time for results.
The reliability of home COVID tests depends on several factors, including how long you’ve been sick, whether you have symptoms, and the type of test you're taking. That makes it tough to put an exact estimate on how effective these tests are.
“The higher the viral shedding, the more sensitive the test is,” says Thomas Russo, MD, a professor and chief of infectious diseases at the University at Buffalo in New York. “But that shedding varies over time and probably peaks on day two to four of symptoms.” (Viral shedding, in case you're not familiar with the term, is basically viral particles that your body gives off when you're sick.) How well you collect a sample matters, too, Dr. Russo says. For example, if you don't swirl the swab the appropriate number of times around each nostril, you may not get enough of a sample to get an accurate test result.
Here’s what some of the most popular at-home tests say about their accuracy rates:
BinaxNow: The company says its test detects 84.6 percent of positive COVID-19 cases and 98.5 percent of negative cases.
QuickVue: Its test detects positive cases 83.5 percent of the time, and negative cases 99.2 percent of the time.
InteliSwab: This company’s test detected 84 percent of positive samples in clinical trials, and 98 percent of negative samples.
Ellume: This test has a 96 percent accuracy in picking up symptomatic cases of COVID-19 and a 91 percent accuracy in detecting cases when you don’t have symptoms.
PCR tests are considered the “gold standard” of COVID-19 testing, according to Dr. Russo. And while their accuracy does somewhat depend on when you test, they're considered the most reliable test you can take. Still, these ones require making a trip to your doctor or local healthcare center and waiting a few days for results.
What types of at-home tests can tell me if I have COVID?
Any at-home COVID-19 test can tell you if you have the virus. These tests work by analyzing your spit or a nasal swab, Dr. Russo says.
Are the COVID tests accurate for the new variants?
Yes, COVID tests are accurate for the new variants, Dr. Schaffner says. Why? Home tests detect proteins called antigens from SARS-CoV-2, the virus that causes COVID-19. Newer variants mostly have changes in the spike protein, which the virus uses to latch onto your cells and make you sick.
When should I use an at-home test?
Dr. Russo recommends using an at-home test when you develop symptoms of the virus. “Since there is a lot of COVID going around, you should go ahead and test,” he says.
How likely are false negatives?
Again, it’s tough to put a hard and fast number on this, but false negatives can and do happen. Maybe you tested too soon after being infected, your sample wasn’t the best, or the test is just being buggy—it happens.
“People have to be cognizant that this could occur,” Dr. Russo says. “Many people will say, ‘I had a sore throat and sniffles, I tested myself once, and it was negative, so I don’t have COVID.’ That’s not necessarily true.”
Worth noting: False positives are “quite unusual,” says William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine. “You’re more likely to get a false negative,” he says.
Basically, if you have symptoms of COVID-19 and you test positive, you definitely have the virus. If you have symptoms and test negative, it’s entirely possible that you have something else—but you could also have COVID-19.
Can you test negative on an at-home test and still have COVID?
Yep, unfortunately. If you test negative but still feel lousy or have symptoms of the virus and are considered high risk for serious complications, Dr. Russo recommends asking your doctor about taking a PCR test. Your healthcare provider should also be able to test you for the flu and other illnesses to see what might be going on.
It's important to know if you do have COVID, both to protect other people you interact with and to get anti-viral medication like Paxlovid to lower the risk of serious complications, Dr. Russo says.
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