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A new COVID-19 test could be able to tell whether someone's caught the coronavirus just 24 hours after they were infected — before they even show symptoms or become infectious themselves.

The test came out of DARPA, the U.S. military's research division, and may be submitted for an accelerated emergency use authorization by the FDA by the end of the week, according to The Guardian.

If the test works as expected, it could play a major role in preventing future outbreaks by letting people know they need to self-isolate well before they start spreading the coronavirus.

"The concept fills a diagnostic gap worldwide," Dr. Brad Ringeisen, head of DARPA's biological technologies office, told The Guardian. He added that, should the FDA approve the test for use, it could be "absolutely a gamechanger."

The test seems to identify cases of COVID-19 about four days sooner than anything else out there, but DARPA scientists told The Guardian that that's not yet a definite number. Should the FDA authorize the test, they would be able to conduct further research and nail down how soon it can spot the disease.

Rather than hunting for the virus, the test verifies that someone is sick by identifying their immune system's response to the disease, which The Guardian reports is harder to miss.

"Because the immune response to infection develops immediately after infection," lead researcher Stuart Sealfon told The Guardian, "a COVID signature is expected to provide more sensitive COVID infection diagnosis earlier."