Criteria for laboratory screening of patients with COVID-19 in hospital settings are proposed to justify treatment, discharge and terms of dispensary follow-up. Optimal approaches are based on the determination of viral load, SARS-CoV-2 viability and serum ferritin level in the dynamics of the disease. High viral load is a criterion for an unfavorable outcome, ferritin level >200 mg/l indicates possible virus persistence. Assessment of SARS-CoV-2 virus viability substantiates a period of infectiousness in COVID-19 patients. At the same time, a longer excretion of the virus with feces is not excluded, which requires further studies to establish or exclude an additional fecal-oral transmission mechanism.