On Thursday, the FDA changed its diagnostic guidelines for SARS-CoV-2, the novel coronavirus that causes COVID-19. Following a change on March 16, the agency opened the door to a number of specific private institutions and laboratories to develop and distribute tests that can deliver on-site results in as little as 15 minutes – but there are some fairly large reservations that are met Remember if you bring more of it to the market.
The tests, which are "serological", that is, identify the presence of antibodies in a person's blood, differ significantly from the molecular tests that are currently being carried out by the FDA-approved laboratories and transit test centers under the EUA (Emergency Use Authorization). The serological tests show that a person has developed antibodies to SARS-CoV-2, which means that they are very likely to have come into contact with (and either have or have already recovered from it). The molecular tests actually detect the presence of viral DNA in the bloodstream, which is a much clearer indicator that they currently have an active infection (at least at the time the swab is removed).
Serological testing was still widely used in countries where the response to the COVID-19 pandemic has been shown to be effective, including China, Taiwan, and Singapore. They have also been used in various US communities based on previous guidelines for private laboratory diagnostics. However, on March 26, the FDA named 29 companies that notified the agency as needed and are now able to distribute their tests.
It is important to note that these tests have not been reviewed or validated by the FDA, unlike the molecular tests that are included in the organization's emergency category. Instead, the FDA intends to “not object to the development and distribution of these tests by commercial manufacturers” 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, especially in people who have come into contact with the virus. Follow-up tests with a molecular diagnosis should be considered to rule out infection in these individuals.
- Antibody test results should not be used as the sole basis for diagnosis or exclusion of SARS-CoV-2 infection or for information on the infection status.
- Positive results may be due to past or present infection with non-SARS CoV-2 coronavirus strains such as HKU1, NL63, OC43 or 229E coronavirus.
In its frequently asked questions about emergency use, the FDA expressly states that these companies have reported their own validation of these tests and are not applying for approval for emergency use. That said, nothing prevents the entities on this list from distributing their tests, which means that they will be able to test Americans and paint a larger picture of the possible spread of the novel coronavirus – with the above limitation that the FDA does not consider these tests used alone as a positive confirmation of a particular SARS-CoV-2 case, or vice versa, as a safe indicator that someone does not have the virus.
In the absence of better options, such as the expanded availability of the EUA-approved tests, these serological tests (many of which can deliver blood on site with just a pinprick) are helpful in providing a more accurate picture of the overall spread and reach of the coronavirus, in particular For smaller clinics, general practitioners and local laboratories that do not have priority access to the equipment and consumables required for molecular testing efforts.
For example, a test on this list, the Healgen Scientific HVG IgM / IgM Rapid Test Device (Whole Blood / Serum / Plasma) does not require instrumentation and can deliver results in as little as 15 minutes. The distributor Ideal Rehab Care works with its legal representative Fox Rothschild to import the tests "as quickly as possible" from Singapore.
The FDA, which has updated their website with Healgen as one of the sites that has notified it of its intention to use its serological test, has given the company the opportunity to start selling: it is still illegal for someone to is not on this list, the FDA continues to explicitly prohibit the use of serological tests at home in accordance with its official guidelines.