Several people have contracted the coronavirus, got better and never got tested. They don’t even know for sure they were exposed because they just stayed home.

After initial infections and the rush to make COVID-19 tests available, a new phase in research is approaching.

Dr. Rudy Alvarez, pathologist and medical director at South Texas Health Systems, is working to get antibody tests. They have decided to go with a product called Celex.

The doctor says it’s undergone more rigorous review by the Food and Drug Administration to detect if somebody has the antibodies they generated from fighting the virus.

Watch the video above for the full report.