What You Need to Know About False Positive COVID-19 Test Results

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The View Has False Positive COVID-19 Test Scare: What to Know and How It Can Happen
The View Has False Positive COVID-19 Test Scare: What to Know and How It Can Happen

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Sunny Hostin and Ana Navarro had a COVID-19 scare last week when they were suddenly pulled from The View stage after testing positive for the virus, despite being vaccinated. But on Monday, it was revealed that their test results were false positives and that, thankfully, neither host was actually infected.

"It was really uncomfortable for my results to be released publicly before I even knew what was going on before they were verified before I was tested again and again," said Hostin, 52, during Monday's episode.

"I was relieved, to say the least, to find out that I was COVID-negative. And I always was assured by the fact that I am fully vaccinated," she continued. "And so, if even if I were COVID-positive, I was convinced that I would likely be okay. And if this type of thing were to happen to me, Ana Navarro is the best person to have it happen with you, because her charm and her wits and her sense of humor really got me through it. I won't tell you the types of things that she was saying in Spanish, but it was pretty terrific." (Related: What Is a Breakthrough COVID-19 Infection?)

Navarro, 49, also reflected on the experience during Monday's show: "Frankly, my first thought was, 'Oh my God' — because I had just spent the day with Kamala Harris' sister, niece, and brother-in-law, so I'm thinking I'm Typhoid Mary and I'm going to wipe out the entire Harris family in one week. So I had to call them [and] immediately call [my] family because you don't want them to find out from TV — of course, they had, and it shows you just how instant, these days, news travels."

While the drama made for interesting view-ing (eh? eh?), it may have also raised some concerns about the possibility of false-positive test results overall. Here's what to know about potential discrepancies in COVID-19 test results.

What Is a False-Positive Test Result?

A false-positive result is when you test positive for COVID-19 despite not actually being infected with the illness, according to Harvard Health.

How Common Is a False-Positive COVID-19 Test?

The accuracy of COVID-19 tests can vary due to a number of factors. For some, it depends on when you get tested and the size of your potential viral load — how much of the virus you're carrying — you have at the time of your test. Generally, asymptomatic, vaccinated patients are most likely to generate false-positive results in their tests, according to the Centers for Disease Control and Prevention. The odds come down to a numbers game: The CDC recommends not testing asymptomatic vaccinated patients due to the likelihood of false positives, noting that in areas where few people are infected and most are vaccinated, you're more likely to see a higher proportion of false positives in test results.

That said, if you are symptomatic, chances are you won't get a false-positive result, notes the CDC, because tests are typically most accurate after patients have shown symptoms (and most accurate within five to 10 days of the first signs of illness). In a March 2021 study of rapid tests across several brands, such tests also showed false positives only one percent of the time in symptomatic patients. (Related: The Most Common Coronavirus Symptoms to Look Out for, According to Experts)

Are Certain Types of COVID-19 Tests More Likely to Net a False Positive Result?

Generally, rapid antigen tests (the type typically used in at-home tests which test for protein fragments specific to the coronavirus) are accurate for symptomatic patients, with 99.6 percent accuracy in positive test results, according to a March 2021 study. Most of the currently authorized antigen tests can return results anywhere between 15 to 30 minutes, according to the CDC. Their individual accuracy can vary slightly in terms of delivering false positives, says Charlene Brown, M.D., public health physician and advisor for Everlywell, an at-home health testing company, though it's still very, very rare.

"Rapid antigen tests are useful if you need results fast, with results available in as little as 10 to 15 minutes," says Dr. Brown. "However, they're generally considered less accurate than PCR tests and may miss some cases. There is also a chance of getting a false positive due to the fact that no rapid test is 100 percent accurate. The accuracy rate varies among each specific test and can often be found directly on the test company's website."

Polymerase chain reaction tests (PCR tests) had a 97.2 percent accuracy rate in a January 2021 study, with a false-positive rate of nearly zero. They're typically most accurate about eight days after infection.

"PCR testing is considered the gold standard in SARS-Cov-2 detection and is generally more accurate than rapid tests," according to Dr. Brown. "The accuracy of PCR tests varies, and often depends on when someone is tested." (Related: How Effective Is the COVID-19 Vaccine?)

What's the Best Way to Assure Your COVID-19 Test Results Are Accurate?

Let's face it: COVID-19 tests are uncomfortable but important. And, more often than not, the best way to get an accurate result is to take more than one test (Sorry!)

"Rapid antigen tests are great for convenience, but there are some tradeoffs for accuracy," says Dr. Brown. "Some rapid tests come in a two-pack for serial testing. Taking both tests can reduce the chance of false positives. It's important to follow rapid antigen tests up with confirmatory PCR testing since PCR tests are more reliable. The FDA-authorized rapid tests that are now available in stores and online tend to be more accurate if you're symptomatic." Dr. Brown adds that PCR tests are more likely to have a false-positive result within the first four days after infection, so getting tested twice within 10 days of exposure to the virus is a good way to ensure you have the most accurate result to keep yourself and others safe.

And, of course, no matter how many or what kind of COVID-19 tests you get, the best protection from the virus is to get the vaccine. For the folks who received the two-dose Pfizer-BioNTech vaccine, you may be eligible to receive a third shot six months after your second inoculation. Currently, those over the age of 65 and people who may be considered immunocompromised (such as recipients of organ transplants) can consider getting a booster.

The information in this story is accurate as of press time. As updates about coronavirus COVID-19 continue to evolve, it's possible that some information and recommendations in this story have changed since initial publication. We encourage you to check in regularly with resources such as the CDC, the WHO, and your local public health department for the most up-to-date data and recommendations.