Moscow started mass testing on May 15, this programme is Enzyme-linked immunosorbent assay (ELISA)
https://www.rbc.ru/society/14/05/2020/5ebd51f99a7947173a1c5b3e
“Every few days approximately 70 thousand Muscovites will receive an invitation to donate blood.
“The selection of residents will be carried out randomly in accordance with the age structure of the population of Moscow and taking into account the district of residence, and invitations will be sent by e-mail or via SMS,” – the mayor said.
Those who receive such an invitation will need to register for blood donation online. Testing results will be summed up every week and will be published on the city site. Everyone who passes the tests will be separately informed about their result.”