Whether you’ve developed the sniffles or just need proof that you don’t have COVID-19, there are many times you may want to get tested for the virus. A year ago you had to visit a doctor or a testing site to find out, but now home COVID-19 tests are available to make your life easier.
Still, these in-home COVID tests are fairly new, so it’s only natural to wonder how effective they really are. While experts agree that you can usually rely on these tests for good results, they point out that there are certain factors that can make a difference in their accuracy. Here’s what you need to know before testing at home.
What are home COVID tests?
Home COVID tests can usually be picked up from a drugstore or other retail store. Rapid tests are the most common; Self-collection tests, where you take a sample and send it to a lab for analysis, are also available.
Many tests require you to take a nasal sample using a swab, according to the Centers for the Disease Control and Prevention (CDC). Others require a saliva sample, which means you spit into a container so the liquid can be analyzed. Every home COVID test is slightly different, which is why the CDC recommends that you read the full instructions before you start the test.
How effective are home COVID tests?
The gold standard continues to be PCR tests, which cannot be done at home, but experts say home COVID tests give fairly accurate results. Home testing companies claim high efficiency rates, although they report their internal data in different ways. These are some of the most common approved by the Food and Drug Administration and available at drugstores (although availability may vary depending on where you live):
Ellume says his test offers 96% accuracy in detecting symptomatic cases of COVID-19 and 91% accuracy in detecting asymptomatic cases.
BinaxNow says its test detects 84.6% of positive COVID-19 cases and 98.5% of negative cases.
QuickVue says its test detects positive cases 83.5% of the time and negative cases 99.2% of the time.
InteliSwab claims its test correctly identified 84% of positive samples in clinical trials and 98% of negative samples.
However, according to experts, home tests are more effective in certain circumstances. “If you have symptoms of a viral disease and your rapid test is positive, then consider yourself infected with COVID-19,” says Richard Watkins, MD, infectious disease physician and professor of internal medicine at the Northeast Ohio Medical University. But, if you don’t have symptoms of COVID-19 and just test to see if you have the virus before doing something like going to a wedding or visiting an elderly relative, you’re more likely to you were getting the wrong reading, says John Sellick, DO, infectious disease expert and professor of medicine at the University of Buffalo / SUNY.
What to know about false positives
“The problem with these tests is that their specificity is not as good as a PCR test,” he says. “You can get false positives, especially in low prevalence settings. This means that if you test positive for COVID-19 with a home test, you are not showing symptoms of the virus, there is not a lot of virus circulating in your community and you are fully vaccinated, you must give the results of the lateral eye and follow them with a PCR test.
Please note: No COVID-19 test is 100% accurate and false readings can also occur with PCR tests. They’re just more likely when you don’t have any symptoms, says Dr. Sellick.
A manufacturing defect can also lead to a false reading. Ellume announced this week that it was recalling specific lots of its home COVID tests due to “an increased likelihood that testing of affected lot numbers could give a false positive result.” Nearly 200,000 test kits have been affected, or 5.6% of the 3.5 million tests the Australian company has shipped to the United States, according to The New York Times. However, Ellume stresses that only affected batches will give false positive results.
Again, home COVID testing is pretty accurate. But if you have symptoms of COVID-19, test negative and your symptoms worsen or lose your sense of taste and smell, Dr. Sellick also recommends getting a PCR test.
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