Dive Brief:

• FDA on Thursday awarded the first emergency use authorization for a blood test to detect coronavirus antibodies. The antibodies can be detected several days after initial infection or later following infection. President Donald Trump at Thursday's White House briefing called the authorization "a key step that will help identify people who have recovered and to understand their immune response and their immune system."
• The test, however, "should not be used as the sole basis for diagnosis and can only aid in the diagnosis of patients in conjunction with a medical review of symptoms and results of other laboratory tests," FDA said in its authorization letter to ​Cellex, a Research Triangle Park, North Carolina-based firm behind the test.
• Other companies and labs, including BD and Mayo Clinic, have already said they're rolling out serology tests, but have not yet received an EUA from FDA. They have the leeway to do so under guidance issued by FDA during the public health emergency.

Dive Insight:

Serology testing is considered an important next step in how the U.S. screens for who has had, or has immunity, to the coronavirus.

The FDA letter of authorization notes that the IgM antibodies the test detects are "generally detectable in blood several days after initial infection, although levels over the course of infection are not well characterized." A second type, IgG antibodies, become discernable "later following infection."

Either antibody could return positive results after infection, which can indicate "acute or recent infection," according to the agency. Use of the test is restricted to CLIA labs certified to carry out moderate and high complexity tests.

In an update Thursday night, FDA said 25 emergency use authorizations had so far been issued for diagnostic tests designed for the novel coronavirus. The list of companies with EUAs to date includes LabCorp, Quest Diagnostics, Roche, Thermo Fisher Scientific, Abbott, Qiagen, PerkinElmer, DiaSorin and GenMark.

One of the newest additions to that list is BD, which on Friday said a test from molecular diagnostics company BioGX that runs on its BD MAX system now has an EUA from FDA. The companies announced the submission March 16. BD said the test allows hospitals labs to screen on site and takes less than three hours to turn around results. Each system can run "hundreds" of tests per day. BD expects these tests will boost national testing capacity by 50,000 tests per week.