Millions of 15-minute COVID-19 tests are coming, but they are less accurate

• Millions of rapid coronavirus tests are estimated to become available to people in the US next month.
• The tests, which can deliver results in about 15 minutes, are inexpensive and easy to produce, and require no lab work.
• But they are generally not as accurate as laboratory PCR tests, and they may need to be performed several times to get an accurate reading about when someone is really sick.
• “I would still say that distance and the outdoors are your best friends,” said one expert.
• Visit the Business Insider website for more stories.

Testing for American coronavirus is about to become much faster.

After months of shortcomings and delays with laboratory tests, the US is beginning to embrace a new kind of diagnostic coronavirus control: the point-of-care test, which can deliver results in about 15 minutes, without traveling to a lab.

“We are not in a situation where every American can wake up every morning and have a test they get before they go to work, but there are enough tests, and that is growing substantially,” said Admiral Brett Giroir. the US coronavirus tests tsar, said in an interview with reporters on Wednesday.

The variation in this quest for faster testing, and more on-site testing at locations such as nursing homes, schools, and businesses, is accuracy.

“I would still say that distance and the outdoors are your best friends, keep that in mind,” said Michael Osterholm, who heads the Center for Infectious Disease Research and Policy at the University of Minnesota, Insider said.

This is because these newer, rapid tests are not as idiotic as the laboratory-type controls that have been in use for COVID-19 for months, the disease caused by the new coronavirus.

Just ask Ohio Governor Mike DeWine, who recently had a rare false positive rapid test before he was assessed to meet with President Trump, an experience that led him to stress that rapid tests “should be seen as a screening,” and not definitive coronavirus diagnostic tools.)

The US plans to have 40 million rapid tests available next month, a dramatic uptick

Test results of Coronavirus in the US typically took several days to return, a delay that helps support the spread of the virus.

“The majority of the tests are absolutely useless because the results do not return in 24 hours,” Bill Gates recently told Insider.

With the virus still taking many pockets of the country, rapid tests – albeit incomplete – are on course to become the country’s next big tool in better combating the pandemic.

“By September, we should have up to about 90 million, nine-zero-million tests available,” Giroir said. “Probably about 40 million of them will be point-of-care.”

If his monthly forecast were true, it would be a remarkable uptick in U.S. tests, more than doubling the number of tests the country has conducted to date (74.8 million so far, according to Giroir).

These tests are intended for people in essential services and vulnerable populations, not for the general public

Giroir argues that the tests may be particularly useful in places with major outbreaks, such as nursing homes and schools.

“Random testing of healthy people, just the whole country, is not what we advocate for,” he said. “Care tests are very helpful if you have symptomatic people, if you make contact, or if you are in a place like a nursing home, where we will check several times.”

Giroir called this rapid market antigen testing an “old school” viral technique that is useful because it is inexpensive, and production can happen quickly. (Antigen testing has previously been used to detect flu and other respiratory viruses.)

“You may lose a little bit of sensitivity, which is what these tests generally do, because you will have repeated tests,” he said. “A little loss of sensitivity, especially in a nursing home, if you can get a quick wrap, beats a very very sensitive test with a wrap of two or three days.”

But many people already use rapid test results in more dangerous ways, as a kind of permission to live life and feast as if the coronavirus did not exist.

“The question is, at what point do you feel comfortable if you are putting yourself or others at risk of infection?” Osterholm said. “These tests can sometimes be a deterrent to practicing good judgment.”

How fast tests work

Most rapid tests work by hunting for the presence of coronavirus antigens in fluid samples collected from a sick person’s nose or throat. Antigen tests scan for pieces of protein that sit on it as in the coronavirus, instead of looking deeper for the genetic code of the virus, such as molecular lab tests (RT-PCR).

Because there are so few of the rapid antigen tests approved for use in the US (but three have so far been licensed by the U.S. Food and Drug Administration), it is difficult to know exactly how well they perform . Osterholm estimates that the tests may include anywhere between 7 and 8 in every 10 coronavirus infections, leaving 20 to 30% of patients with coronavirus in the dark about their status, and blissfully think they are virus-free. (A false positive test result, like DeWine’s, is rarer than a false negative.)

“Rapid antigen tests are especially useful when the person is being tested in the early stages of infection,” the U.S. Centers for Disease Control and Prevention said in a statement about the rapid tests released last week, emphasizing that they work best on people with a high viral load (usually a person’s viral load is highest in their first day or two of infection).

Quick tests should not be used as a permission loop to be memorable

Cheap rapid tests have already been sent out to other places around the world to track the virus, including in free government tests on the streets of New Delhi, India, and among sports teams and holidaymakers in the UK and Poland.

But even if rapid results of coronavirus tests are more often than not accurate, they are now no free passport for carefree living. Being close to other people and their germs is still a risky prospect.

“A negative test on one day does not mean you will be negative the next day,” Giroir said.