SAN JOSE, Calif.—A former Theranos Inc. lab worker testified Wednesday that she raised alarms about the blood-testing startup’s practices with colleagues, managers and even a top executive and a board member but was rebuffed at every turn.
The testimony of the former employee, Erika Cheung, bolstered federal prosecutors’ case against Theranos founder Elizabeth Holmes, who is battling accusations that she defrauded patients and investors with promises that her technology could test for a range of health conditions using just a few drops of blood from a finger prick.
