The FDA just okayed multiple 15-minute blood tests to screen for coronavirus, but there are caveats

On Thursday, the FDA amended their emergency policy around diagnostic testing for SARS-CoV-2, the novel coronavirus that causes COVID-19. Following on a change made March 16, the agency opened the door for a number of specific private entities and labs to develop and distribute tests that can provide results on the spot in as little as 15 minutes - but there are some pretty big caveats to keep in mind as you hear about more of these coming to market.

The tests, which are "serological," meaning they identify the presence of antibodies in a person's blood, differ considerably from the molecular testing that is currently in use under Emergency Use Authorization (EUA) by FDA-approved labs and drive-through testing sites. The serological tests show that a person has developed antibodies to SARS-CoV-2, which means they very likely came into contact with it (and either have it, or have already recovered from having it). The molecular tests actually detect the presence of viral DNA in the blood stream, which is a much more definitive indicator that they currently have an active infection (at least at the time the swab was taken).

Serological tests have still been used widely in countries where the response to the COVID-19 pandemic has been shown to be effective, including in China, Taiwan and Singapore. They've also been used in different communities in the U.S., based on earlier guidelines around private lab diagnostics. But on March 26, the FDA named 29 entities that provided notification to the agency as required and are now therefore able to distribute their tests.

It's important to note that these tests have not been reviewed or validated by the FDA, unlike those molecular tests that are included in the organization's emergency use category. Instead, the FDA "does not intend to object to the development and distribution by commercial manufacturers" of these tests, provided they meet a number of criteria, including qualifying the results of their reported test results with the following information:

• This test has not been reviewed by the FDA.
• Negative results do not rule out SARS-CoV-2 infection, particularly in those who have been in contact with the virus. Follow-up testing with a molecular diagnostic should be considered to rule out infection in these individuals.
• Results from antibody testing should not be used as the sole basis to diagnose or exclude SARS-CoV-2 infection or to inform infection status.
• Positive results may be due to past or present infection with non-SARS-CoV-2 coronavirus strains, such as coronavirus HKU1, NL63, OC43, or 229E.

The FDA specifically notes in its emergency use FAQ that these entities have reported their own validation of these tests, and that they won't be pursuing Emergency Use Authorization. That said, there's now nothing stopping the entities on this list from distributing their tests, which means they will be able to be put to use in testing Americans and painting a larger picture of the potential spread of the novel coronavirus - with the caveat noted above that the FDA doesn't consider these tests used alone to be positive confirmation of a definite SARS-CoV-2 case, or conversely, a sure indicator that someone doesn't have the virus.

Still, in the absence of better options like expanded availability of the tests that are approved under the EUA, these serological tests (many of which can provide on-site results with just a pinprick of blood) will be useful in painting a more accurate picture of the overall spread and reach of the coronavirus, especially for smaller clinics, GP clinics and local labs that don't have priority access to the equipment and supplies needed for the molecular testing efforts.

For instance, one test on this list, the Healgen Scientific COVID-19 IgG/IgM (Whole Blood/Serum/Plasma) Rapid Test Device, requires no instrumentation and can provide results in just 15 minutes. Distributor Ideal Rehab Care is working with its legal representation Fox Rothschild to begin importing the tests from Singapore for use "as soon as possible."

The FDA updating its website with Healgen as one of the entities that have notified it of intent to use its serological test is what unlocked the ability for the company to begin distribution: It's still illegal for anyone not on this list to do so, and the FDA still also specifically prohibits the use of at-home serological tests on its official guidelines.