This literature review is aimed at exploring the significance of laboratory parameters in the follow-up of the coronavirus disease-19, which is the latest global biohazard for humanity. Laboratory parameters were classified under three main headings. These headings were hematological tests, inflammatory parameters and coagulation parameters. It has been determined that low lymphocyte count, which is one of the hematological tests, is a condition seen at every stage of the disease. High neutrophil counts are evident in worsening the course of the disease. The neutrophil/lymphocyte ratio increases with increasing disease severity. Low platelet levels may also be observed. It has been determined that high C-reactive protein (CRP) levels can be seen at every stage of the disease. In addition, as the prognosis of the illness worsened, C-reactive protein levels were found to increase more. Increased prothrombin time and high D-dimer values are evident in coagulation tests in patients with severe coronavirus disease-19. In addition, increased ferritin and procalcitonin levels are observed as the illness course worsens. As a result, lymphocytopenia and increased CRP levels come to the fore in the illness course. When the illness becomes more aggressive, prothrombin time, neutrophil/lymphocyte ratio, neutrophil count, D-dimer, ferritin and procalcitonin levels draw attention.