Home COVID-19 Tests: How Do They Work & Are They Accurate?

Everything you need to know about the at-home tests that are flying off drug store shelves.

At-home Covid test

The days of waiting in long COVID-19 test lines may be over.

Now, companies are selling over-the-counter kits that make at-home testing quick, convenient, and accessible. Some retailers will be offering these tests for free in order to help stop the spread of the Delta variant.

Still, the recent fiasco on ABC's "The View," where hosts Sunny Hostin and Ana Navarro had to abruptly leave the set — right before Vice President Kamala Harris was set to appear live — due to what is now being called "false-positive" tests, has made the country question their efficacy.

What Are At-Home COVID-19 Tests?

Many of the at-home COVID-19 tests are similar and test for COVID-19 antigens, which basically means, "Do you have COVID-19 right now?" Each one contains a nasal swab, a bottle of liquid reagent, and some sort of indicator. In most cases, you swab your nose, the swab goes into the liquid, and the indicator shows you the results.

But some tests are more high-tech — such as using Bluetooth and an app on your phone. Some tests even have apps that provide a real person to check your ID and monitor you as you take the test and then confirm the results. You can then get a QR code that certifies the results of your test. Some at-home tests provide this service with the test, while others may charge an extra $15.

Each test has slight differences, so it's important to read the instructions.

What's the Difference Between a Rapid Antigen Test and a Polymerase Chain Reaction (PCR) Test?

The at-home antigen tests look for pieces of the protein and typically take only 15 to 30 minutes. Rapid antigen tests are most accurate when used within a few days of the start of your symptoms, which is when the largest amount of virus is present in your body.

PCR tests detect RNA, the genetic material of the virus. These tests are more accurate, but the results take longer: typically up to three days. While there are some at-home PCR tests hitting the market, most can not be done at home. Talk to your doctor for more information.

Why Are There Two Tests in My Kit?

Most at-home testing kits come with two tests that you are supposed to take one or two days apart. Taking multiple tests helps to increase the accuracy of the results.

How Accurate Are the Results?

Dr. Michael Crupain, The Dr. Oz Show's chief medical officer, says that despite the recent on-air situation at "The View," the tests can be trusted.

"Whenever you screen lots of asymptomatic people, like in a workplace screening program, you are going to end up with false-positive tests," Crupain said. "The most common causes are contamination. Knowing this can happen is key, and having a plan to repeat testing with a higher quality test can help reduce the disruptions false positives cause."

But this doesn't mean you should skip an at-home test if you're feeling symptoms or have been around someone who has been exposed to COVID-19.

"I would say these are good tests," Crupain said. "Their accuracy is good, but not as good as PCR. On the other hand, you get the result in minutes rather than days. The key is to use the tests the right way. If you have a positive on a rapid test you should follow up with a PCR. If you have a negative you should follow the test instructions and test again as appropriate."

Where Can I Get an At-Home Test?

Many state and local governments are giving away at-home tests for free at community centers, shelters, food banks, testing sites and more. Check your city's website for more information. Many of the FDA-approved at-home tests are also available over-the-counter for purchase at your local drug store.

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