Может кому-то будет актуальна информация по ПЦР. Ответ:
Градски завод за јавно здравље Београд
There is no need to make appointement, You just need to pay in any bank or post office, use following instruction and come in Institute of public health of Belgrade, Bulevar despota Stefana 54a, from 07:30 t0 12:00h. You will get result in email, same day after 17:00h.