(Bloomberg) --

The U.K. has ordered 3.5 million home-testing kits that show whether someone has been exposed to the coronavirus, and they’ll be available within days, a health official said.

The tests will be made available when scientists from Oxford University finish evaluating them for public use, according to Sharon Peacock, director of the U.K.’s National Infection Service.

The blood tests, which check for antibodies against the coronavirus, will be sold via Amazon.com Inc. and pharmacy chains so people can test themselves, Peacock told a panel of lawmakers in Parliament. The effort is part of Prime Minister Boris Johnson’s push to scale up monitoring of the disease after his government faced criticism for not carrying out enough testing.

So-called antibody tests could turbocharge the testing process, giving people who’ve been unable to confirm whether they’ve been infected or haven’t experienced symptoms a cheap and easy way to find out whether they’ve been exposed. That would enable countries to better understand how widely the disease has spread, informing policy decisions about whom to quarantine and when certain economic or social activities can be resumed.

The approach is less reliable than the molecular diagnostic tests that are used to determine whether someone is currently infected. Those tests, which have confirmed the more than 440,000 cases known globally, look for nucleic acids of the virus in people’s samples. Scientists have spent recent weeks comparing just how reliable the antibody tests are compared with the molecular tests.

Antibody tests sometimes produce false negatives, since people only develop antibodies against the coronavirus several days after being exposed. And they can result in false positives, too, if someone has developed these antibodies while fighting a different coronavirus. Even so, the tests could provide an easy way to see who appears to have developed some resistance to the virus, potentially letting them back into hospital work.

©2020 Bloomberg L.P.