Thank You, to the Guardian for this story. "Scientists working for the US military have designed a new Covid-19 test that could potentially identify carriers before they become infectious and spread the disease, the Guardian has learned.

In what could be a significant breakthrough, project coordinators hope the blood-based test will be able to detect the virus’s presence as early as 24 hours after infection – before people show symptoms and several days before a carrier is considered capable of spreading it to other people. That is also around four days before current tests can detect the virus."

https://www.theguardian.com/world/2020/may/01/us-germ-warfare-lab-creates-test-for-pre-infectious-covid-19-carriers