The promise of coronavirus antibody tests has been hampered by reports that many are inaccurate. Now the Food and Drug Administration has given emergency authorization to a test developed by drug giant Roche, which says preliminary sampling of 6,000 people showed it is 100 percent accurate in determining whether someone has COVID-19 antibodies, which means they were infected in the past. Roche says the tests are 99.8 percent accurate in ruling out antibodies, The Wall Street Journal reports. If these results hold up, it could be a major breakthrough because many epidemiologists say widespread antibody testing would provide crucial data for determining whether to ease up on lockdowns.