Today, the U.S. Food and Drug Administration approved the initial two COVID-19 serology tests which show an estimated amount of antibodies within somebody's blood. Both tests from Siemens, the ADVIA Centaur COV2G and Attelica COV2G are what are known as"semi-quantitative" evaluations, meaning that they don't show an exact measurement, but estimate the number of a patient's radicals generated from infection with the virus that leads to COVID-19.

"Having the ability to quantify a patient's relative degree of antibodies in response to some preceding SARS-CoV-2 infection could be useful as we continue to learn more about the virus and what precisely the existence of antibodies may mean," said Tim Stenzel, M.D., Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological Health. "There are still many unknowns about what the presence of SARS-CoV-2 Compounds may inform us about possible immunity, but now's authorizations provide us additional tools to evaluate those Compounds as we continue to research and examine this virus. Patients shouldn't interpret results as telling them how they're immune, or have some amount of immunity, from the virus."
Because of those unknowns, the FDA warns patients against using the results from such tests, or any serology test, as an indication that they can stop taking steps to protect themselves and others, such as stopping social distancing, quitting sporting masks or returning to work. The FDA also wishes to remind patients that serology tests should not be used to diagnose an active disease, as they only detect antibodies the immune system develops in reaction to this virus - not the virus itself.