The coronavirus pandemic 2019 (COVID-19) is changing the world and reshape all aspects of life. Side by side to global efforts to develop potential vaccines and effective drugs against COVID-19, clinical parameters scanning the prognosis of COVID-19 infection are badly required to help the clinicians in premature management of COVID-19 cases before critical progression. The main objective of our study is to specify reliable biomarkers which differentially change upon case progression and clearly reflect the extent of lung lesions. Forty-one patients from Mansoura area, confirmed for COVID-19 infection were classified according to the diameter of lung lesions measured by lung computed tomography (CT) into mild and severe cases including 66% and 34% of all patients, respectively. COVID-19 patients were followed since hospital admission for comparative studies covering measured biochemical and hematological parameters. Based on the degree of severity, five different biomarkers mainly; D-dimer, lactate dehydrogenase (LDH), C-reactive protein (CRP), lymphocytes and ferritin were found to clearly oscillate in response to COVID-19 infection and upon case transition from mild to severe. In our study, significantly higher levels of almost all the biomarkers except lymphocyte count, were detected in patients having severe complications of COVID-19 infection in contrast with non-severe patients.