The Food and Drug Administration (FDA) has approved the first test of its kind in the U.S., an antibody test intended to diagnose COVID-19.

Developed by biotech and medical diagnostics company Cellex, the purpose of the test is to confirm whether antibodies are present in a given blood sample taken directly from a patient--antibodies which would've resulted from the body's detection of the 2019 novel coronavirus SARS-CoV-2, the virus that causes the disease COVID-19.

Results of the test, which look for antibodies immunoglobulin M and immunoglobulin G, are available within only 15-20 minutes. According to Live Science, "immunoglobulin G is specific to the coronavirus."

The FDA concluded earlier this month that "emergency use" of the test was necessary. "Based on the totality of scientific evidence available to FDA," the agency wrote in a letter to Cellex CEO James X. Li, Ph.D., "it is reasonable to believe that your product may be effective in diagnosing COVID-19."

This type of diagnostic test can be used to diagnose individuals who either currently have COVID-19 or previously did and recovered, which is mostly why the test is so valuable. Previous tests in development have intended to diagnose current ongoing cases.

Considering the nation's rapid response to prevent, treat, and diagnose COVID-19, additional antibody tests have been developed and approved in the U.S. since the FDA authorized its initial approval of Cellex's test.

One such additional test was developed at Mount Sinai Hospital in New York City. According to Mount Sinai, their lab could process 2,000 tests per day. More than that, however, wouldn't be feasible given their size. "We'll never do more than maybe 2,000 tests per day because we're not at the scale that commercial laboratories would be," said David Reich, president and COO of Mount Sinai Hospital.

The Mount Sinai lab is affiliated with the National COVID-19 Convalescent Plasma Project, a coalition which is looking at the possible impact of plasma transfusions on COVID-19 cases.

Other companies, such as United Biomedical, had already developed and begun using antibody tests without receiving previous authorization from the FDA.