The U.S. Food and Drug Administration has authorized the emergency use of six at-home collection kits to test for the coronavirus, but experts say their accuracy and affordability is in question. Some of the newer test kits use saliva samples, while others require a more invasive nasal or throat swab.

The kits are much-needed additions to our sparse testing resources, but the samples collected still need to be sent to laboratories to get results, according to The Wall Street Journal. The market for at-home tests is huge, including those who are disabled or immune compromised and are better off testing at home, and college students and workers who want to return to their schools and jobs safely. According to the Journal, sales of these COVID-19 tests could reach as high as $816 billion this year.

One of the downsides, however, is their accuracy. While some test kit manufacturers send professional healthcare workers to the home to extract samples, people who take their own samples may invite too many variables that can taint the results.

That's why the newer saliva tests are more appealing, said the Journal. It's easier to spit into a tube than insert a swab up the nose. But Dr. Alan Wells, professor of pathology at the University of Pittsburgh, said that a sample taken from saliva or a even a nose swab could return a false negative result if the disease has already moved into the lungs. Wells told the Journal that sampling from the nostril or saliva increases the rate of false negatives by 10% to 20%.

"I would trust a positive test result as being positive," he said. "If you get a negative, it doesn't mean it truly is negative."

Another downside is the price. Not all tests are covered by insurance. Laboratory Corp. of America Holdings offers a nasal swab at-home test specifically for the SARS-CoV-2 virus that causes COVID-19 for $119, which health insurers will pay upfront. This week, the FDA approved a coronavirus testing kit from Quest Diagnostics that sends the nasal swab sample via FedEx to a testing lab, according to BGR.

According to GoodRx.com, the at-home tests are not FDA approved but were authorized by the agency under an Emergency Use Authorization. All test services require some type of questionnaire or online consultation to asses COVID-19 risk.