Know how rapid antigen tests work

Health authorities are increasingly highlighting the necessity of rapid antigen tests as a means of preventing the spread of COVID-19, particularly now that the delta variant is causing an increase in new cases and omicron is emerging as a possible hazard.

These over-the-counter diagnostics, which became available in spring 2021, need just a short swab of the nose and provide results in approximately 15 minutes. And their price tag may soon drop to zero, as the federal government prepares to make them available for free at health facilities and private insurance companies pay the cost of buying rapid antigen tests kits.

How trustworthy are these rapid antigen tests? And at what point should you consider one? Top professionals address frequently asked issues and provide helpful hints for doing a COVID test at home.

Know how rapid antigen tests work

How are fast home testing conducted?

As with many COVID rat tests done at doctor’s offices and testing locations, an at-home version uses a swab of your nose to identify whether you’re infected with the coronavirus. These rapid antigen tests, dubbed antigen tests, seek the presence of coronavirus-specific proteins. If they are found, they provide a positive response on a test strip within minutes, similar to a home pregnancy test.

“And that’s beneficial because it enables you to make more informed decisions about how you avoid contact with other people, how you obtain medical care, and how you can break transmission cycles through your behavior,” Cameron Wolfe, M.D., an infectious disease specialist at Duke Health and an associate professor at Duke University School of Medicine, explained in a recent briefing.

When should you do an at-home examination?

Even if you are completely vaccinated, it is prudent to do an at-home test if you are experiencing COVID-19-related symptoms or have been exposed to the virus, according to the Centers for Disease Control and Prevention (CDC). Additionally, self-swabbing is suggested before meeting inside with people – whether for dinner with a small group of friends, a holiday gathering with family, or a major event, such as a concert.

“I would propose rapid antigen tests as a screening tool,” Stephen Kissler, a research fellow in the Harvard T.H. Chan School of Public Health’s Department of Immunology and Infectious Diseases, told reporters on Dec. 7.

The usual PCR rapid antigen tests (short for polymerase chain reaction) available at many doctor’s offices and testing centers may take days to complete. “And frequently, by the time you get the test back, the result is no longer significant,” Kissler explains since it is conceivable that you become sick during the waiting period.

However, Gigi Gronvall, a senior researcher at the Johns Hopkins Center for Health Security and an associate professor at the Johns Hopkins Bloomberg School of Public Health, believes that a fast test performed at home delivers “immediate, actionable answers.” “If you test positive, avoid contact with other people; you have an infectious virus in your nose.” As such, it is an effective public health measure for ensuring that potentially infectious individuals remain isolated.”

The trick is to schedule the test as closely as possible to your plans — ideally on the same day, as Matthew Binnicker, head of clinical virology at the Mayo Clinic, stated in a recent briefing. “That will provide you with the most accurate information about whether someone has a high level of the virus in their system at the moment.”

Which at-home test is the most effective?

The Food and Drug Administration (FDA) has approved many over-the-counter home testing rapid antigen tests kits, and a small number are now accessible in pharmacies and large stores, however high demand may make them difficult to locate in certain places. learn more about them by clicking here

That is why the best test is “the one you can get on the shelf at your neighborhood supermarket,” Kissler adds, noting that the majority of rapid antigen tests “had quite equivalent sensitivity and specificity for identifying SARS-CoV-2,” the official name for the virus that causes COVID-19.

If you purchase your test online from an unknown merchant, be careful to verify that the product is FDA-approved for emergency use, since the FDA has seen counterfeit rapid antigen tests kits being offered on the internet. This should be prominently displayed on the packaging. Additionally, you may verify the list of permitted COVID rapid antigen tests on the FDA’s website.

rapid antigen tests
Rapid antigen detection test (RADT) with two red stripes showing a POSITIVE result of a human sample testing. Mans fingers holding the white plastic device with a COVID-19 Ag inscription.

Additionally, check the label to determine the duration of the effects; this might make or break your choice to choose one brand over another.

“I like rapid antigen tests that provide findings quickly, since usually when I take a fast test, I’m on my way someplace and want to know whether or not I’ve contracted the virus,” Kissler explains. “As a result, a test that returns a result in 10 or 15 minutes is somewhat more convenient for me than an hour-long test.”

Another element to consider while picking a test is its ease of use. Certain rapid antigen tests kits need you to weave a long swab through a card-shaped reader, while others require you to soak a test strip in a vial of solution. “It’s more of a personal taste,” Kissler observes.

How reliable are the findings of COVID home rapid antigen tests?

True, PCR rapid antigen tests are more sensitive than antigen testing, which means you’re less likely to obtain a false negative. However, Gronvall notes that antigen testing is “very accurate when you are most infectious.” “They are, in fact, equal to PCR for the period during which you are most hazardous to others.” According to a recent study done by experts at Johns Hopkins University School of Medicine, fast antigen testing effectively discovered the coronavirus in 87 percent of hospitalized patients with symptomatic COVID-19 and 71 percent of those with asymptomatic episodes of the disease.

False positives with rapid antigen tests are uncommon, Gronvall notes. Therefore, if you test positive for COVID using an at-home test, you should separate yourself from others. You may always confirm the diagnosis with a follow-up PCR or another antigen test, Gronvall notes, since “the accuracy of your result increases with several testing.”

If the test results are negative, it implies the virus was not detected, but it does not entirely rule out infection, according to the CDC. It is possible that your illness is in its early stages and there is insufficient virus in your sample to for the test to be positive. Repeating the test at least 24 hours later will provide further light on the situation. For this reason, some home rapid antigen tests kits include two rapid antigen tests.