The Covid-19 pandemic brought several challenges to the healthcare system: diagnosis, treatment and measures to prevent the spread of the disease. With the greater availability and variety of diagnostic tests, it is essential to properly interpret them. This paper intends to help dialysis units concerning the use of clinical criteria and diagnostic tests for decision making regarding the discontinuation of isolation of patients with suspected or confirmed Covid-19, as well as the return to work activities for employees with suspected or confirmed Covid-19.