The role of laboratory diagnostics is crucial in the control and monitoring of COVID-19 disease using already well-known laboratory parameters as very important in monitoring the treatment of patients, especially for early detection of complications of COVID-19 disease. Here it is necessary to specify the inflammatory parameters that are crucial in monitoring the development of diseases such as CRP, ferritin and PCT. CRP is a sensitive systemic indicator of acute inflammation, infection, and tissue damage. Serum concentration is proportional to the strength of the inflammatory response, so monitoring the increase during disease development is a significant indicator of disease severity and the development of complications. Procalcitonin has a role in distinguishing bacterial from viral causes of infection because in viral infections the release of procalcitonin is suppressed and its values are below the limit. In the severe form of the disease COVID-19, due to its poor general condition, its values are elevated and it is used primarily to exclude bacterial coinfection. Routine biochemical and hematological tests have been reported to be useful in stratification and prognosis of patients diagnosed with coronavirus disease (COVID-19), correlated with poor outcomes such as the need for mechanical ventilation or intensive care, progression to multisystem organs, failure and / or death. Although these tests are already well established in most clinical laboratories, there is still debate about their clinical value in the treatment of COVID-19, as well as the value of clinical risk assessments in predicting COVID-19 disease.