as the us begins to consider letting people go back to work and lifting socialdistancing rules a new debate over testing is emerging researchers are racing to backfill the gaping holes left by shortfalls in diagnostic tests for currently infected patients with newly developed tests that can indicate if a person had covid19 previously these test which measure antibodies in the blood and are being used in studies across the us and the rest of the world are crucial to understanding covid19 and the virus that causes it as theyre rolled out they can tell researchers and government leaders not just how many people are sick but also how many have encountered the virus at all that in turn may at last give a firmer idea of how deadly the virus is and how many people potentially have some level of immunitywe cant see the virus we can track it its footprints in people this is our best way to do that said eric topol director of the scripps research translational institute we need to use this in conjunction with other means to try to restore some relative normalcyseveral studies already are underway so far early research suggests there are significant numbers of people who contract covid19 and dont show symptoms but there arent nearly enough of them to create widespread herd immunity that would build a societywide wall against infection and cause the virus to die out were not anywhere near herd immunity topol said an order of magnitude away at the leastthe tests search for antibodies the immune systems often longlasting response to an infection in the blood instead of testing for the virus itself the tests are typically conducted with drops of blood from a finger or a draw from a vein read more testing troubles persist as us hopes to open back up but like the diagnostic tests that use a nose or throat swab to check currently infected patients the blood antibody tests are proving to be a complex endeavor hamstrung by many of the same issues as well as new onesa stanford university study published online friday prior to peer review concluded that more than twice as many people were infected with covid19 than current counts suggest a number that would indicate it is both more widespread and less deadly than previously understood this would mean santa clara county in california which has had more than 1800 positive cases identified only one out of every 50 to 85 people who actually have covid19the study quickly drew criticism from experts it used facebook ads to seek volunteers who experts said may be more likely to have interest in such a test because they had symptoms compared with a random sample of the population some also questioned the accuracy of the test itself they assumed really really high specificity natalie dean a university of florida biostatistician said using the term that indicates the rate at which false positives occur but the reality is that