RELATED STORIES & VIDEOS:

SAN FRANCISCO (KGO) -- It's the next frontier of COVID-19 testing - looking for antibodies to the virus.ABC7 news got an inside look at the San Francisco lab that is validating a coronavirus antibody test."We're excited about it, especially the results that we're getting," said Kara Lynch, a UCSF Associate Professor of laboratory medicine and co-director of the clinical lab at Zuckerberg San Francisco General Hospital.Lynch and a team have tested 500 blood samples from 80 patients, who are positive for coronavirus. They are able to use remnant blood samples from routine clinical testing, already being performed on patients, to check how antibody levels change."We basically spent the last month validating the method - and if you could see the increase and rise in the antibody response over time - because that has not been well characterized yet for this virus."Their tests revealed that people develop coronavirus antibodies two to 15 days after the onset of symptoms.Next week, Lynch's lab expects to start using the antibody tests on patients and employees within San Francisco's public health system."Antibodies can show if someone has had a previous infection and this is important because we are not able to do swabs on every single individual in the population, so it's helpful to know the extent, how widespread the infection is."Lynch also says it will be helpful to test health care workers who have potentially been exposed the virus."If a health care worker has the antibodies, then they would be at decreased risk of acquiring the virus, so they could potentially be more on the frontline of fighting this and helping those that are infected acutely."Widespread antibody testing could potentially get more people back to work sooner and reveal how long COVID-19 has been circulating, but more research is needed."The only risk is that we don't know for sure if the presence of antibodies means that someone is immune. We're hopeful, because that is what happens with many viruses."To get an antibody test, it must be ordered by a doctor. More healthcare systems will likely start testing later this month.Lynch says she does not expect a reagent shortage, like the one that crippled virus testing last month.