With no clear answer to when life will return to normal, experts say people who have been infected and recovered may be immune to coronavirus. Their blood could hold the key to understanding where we go from here.

A single drop of blood could soon determine if you're immune to coronavirus. The Los Angeles County Health Department is now randomly testing 1,000 people for antibodies, which are produced in our blood to fight infections. Dr Neeraj Sood is heading up the study.

"That will tell us what is the true trajectory of this epidemic," Sood said. "Are infections rising rapidly? Or have they started to plateau? Are we achieving herd immunity? Is this epidemic going to end? When is this epidemic going to end?

And that could determine when it's safe for Americans to return to work, says the dean of the Stanford School of Medicine, Dr. Lloyd Minor.

"The hope is that the information from the antibody tests and other information will enable policymakers to make informed decisions about when shelter in place and social distancing can be relaxed," Minor said.

S far, more than 70 companies want to sell antibody tests kits, with very little FDA oversight.

"These antibody tests, presently, the ones on the market are not very accurate," said CBS News medical contributor Dr. David Argus.

That's a huge problem, Argus said.

"If I do a test and say, hey, you're immune so you can go out and take care of somebody with the virus and you're not immune, you can spread it to somebody who may be very vulnerable," Argus explained. "And so, the decisions on this test really are critical. And so I'd rather no tests than a faulty test."

Another important takeaway from these antibody tests is that they're now checking people who don't have symptoms. That will give a better picture of just how far the virus has spread. First results from the tests in Los Angeles are expected by the end of the week.