Until recently, most testing for COVID-19 required a sample to be sent to a laboratory for processing. While confirmation still requires a laboratory test, over-the-counter rapid antigen tests provide results in as little as 10 minutes.
Health officials say these rapid tests are a valuable tool that can help us better screen for infections and slow the spread of the coronavirus.
How do the antigen tests work?
The at-home, rapid tests detect small viral proteins, called antigens, located on the surface of the COVID-19 virus. While polymerase chain reaction tests, commonly called PCR tests (the kind you get at a doctor’s office), can detect even smaller amounts of coronavirus, rapid tests are highly sensitive and usually detect anyone with enough viral load in them to be a threat to others.
How accurate are the results?
A large analysis found that the rapid tests detected about 72% of symptomatic cases confirmed positive by a PCR test. The rapid tests were less sensitive when testers were not showing symptoms, catching on average about 58% of those cases. Other studies found that the tests detect 93% of cases with a solid chance of being transmissible to others.
If you get a positive result but have no symptoms and no known exposure, take another test—ideally with another brand. Experts say that the likelihood of getting two false positives is so low that if one test comes back negative, you can trust it. If you test positive twice, then you likely have COVID-19.
When and how should I use one?
Rapid antigen tests are a good option for people who may have been exposed to the virus, want extra assurance after traveling to a virus hot spot or before visiting someone vulnerable. However, keep in mind that the rapid tests only test that moment in time. Test yourself as close to your visit as possible, particularly before visiting someone high-risk for severe COVID-19.
In most cases, you will use a long swab to gently scrape the inside of both nostrils and then insert the swab into a special card reader or dip the swab in a solution and use a test strip before waiting 10 to 15 minutes for the result. Each test involves a slightly different procedure, which should be followed to help ensure accuracy.
The Centers for Disease Control and Prevention (CDC) has these helpful videos on How to Use a Self-Test and How to Interpret Self-Test Results.
According to experts, people with COVID-19 symptoms can immediately take a rapid antigen test. However, those with a known exposure should wait three to five days before testing. Testing too soon, before the virus has had a chance to replicate, increases the odds of a false negative.
If you’re using the rapid test because a business, travel authority or organization is requiring proof of a negative test, check in advance to see if they accept the results of at-home tests. You may be required to get a PCR test.
I got a positive result, now what?
If you get a positive result, it’s a pretty sure sign you’re infected, though false positives do happen. You may want to confirm it with another rapid test about 36 hours later or get a PCR test. Experts, however, recommend that you do not wait for the results of a second test to take precautions. You should:
Where can I buy a test kit?
Many brands of rapid, at-home tests are available, including Abbott’s BinaxNOW, Quidel’s QuickVue, Australia’s Ellume and Acon Labs’ Flowflex. The tests usually are packaged two per box and cost under $25. These test kits are available in many pharmacies and drugstores, including Amazon, Walgreens, CVS and Walmart. If a store is sold out of a rapid test, you may be directed to a different type of test, which requires you to mail the sample to a lab to get the result.
One note of caution: fake and unauthorized at-home testing kits are popping up online as opportunistic scammers take advantage of the spike in demand. When shopping for a test, look for a brand that the Food and Drug Administration has authorized.
Private insurance companies must cover eight at-home rapid tests per individual covered per month. That means a family of four, all on the same plan, would be able to get 32 of these tests covered by their health plan per month. Depending on your insurance, you may need to pay for the tests upfront and then submit for reimbursement of the at-home tests. The Centers for Medicare and Medicaid Services has more information on how to get your at-home tests for free.
Currently, Medicare recipients are not eligible for reimbursement of at-home rapid tests because the federal laws governing Medicare do not allow self-administered tests.
How can I get a free test kit?
The federal government has also established COVIDtests.gov, a website where every home in the U.S. is eligible to order four free at-home COVID-19 tests. The tests are completely free and usually ship in 7-12 days after ordering. Individuals who have difficulty accessing the internet or need additional support can call 1-800-232-0233. Currently, only four tests are available for each address, regardless of the number of occupants.
The federal government is also providing up to 50 million free, at-home tests to community health centers and Medicare-certified health clinics for distribution at no cost to patients and community members. Additional information about testing resources for people without insurance is available here.
Washington state also offers free at-home test kits for Washington residents at Say Yes! COVID Test. Officials warned that initial supplies would be limited until the state received additional supplies. Free test kits in Alaska and Oregon are available through local health departments and their community partners.
In-person testing resources
If you are unsure about conducting a rapid, at-home test, you can get tested in person. Please do not come to the Emergency Department for COVID-19 testing unless you require emergency care for your symptoms. We do not offer testing to the public in our EDs. There are many resources available to find in-person testing locations, including: