Tests for the coronavirus are limited in the United States, which means people who aren't showing strong signs of the disease are likely to go undetected.
A new blood test could change that as the country works overtime to screen thousands for the virus and contain it.
These tests can quickly identify disease-fighting antibodies in those who may be infected, but have few or no symptoms.
All it takes is a prick of the finger - different from the current diagnostic tests with a nasal swab that can be hard to come by.
California-based Biomerica is among private companies already selling the test outside the U.S.
They say their kit sells for less than ten dollars.
Company CEO Zack Irani-Cohen warns though - that just because someone has antibodies- doesn't mean they're covid-proof.
"What our test tells you is that they've been exposed to COVID-19, are producing antibodies to COVID-19, okay? And there are some papers that suggest that they will have a likely immunity to it. So there are clinical studies that suggest that they will have a likely immunity to it. COVID-19 is very new. It is novel. And so we don't have all the answers yet."
Disease experts say COVID-19 immunity could last for several months or more than a year based on other coronavirus studies.
But they also caution there's no way to know for sure, and it could be different from person to person.
Tony Mazzuli is the chief microbiologist of Toronto's Sinai health system.
"If somebody has recovered, hopefully they've made theappropriate immune response and therefore you can find these antibodies, thetwo questions are: are those antibodies enough to protect them from gettingre-infected? So can they go back to work, to school, their daily activities,knowing 'I'm immune'? And how long would they last?"
Questions remain over how accurate the tests are - and how they would be rolled out.
The U.S. Centers for Disease Control and Prevention said it is working on its own version of antibody tests, but it has not given a timetable.