The coronavirus spread rapidly throughout the country and around the world, novel coronavirus was later identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The whole world is racing to find a vaccine or a drug or repurpose already existed drugs to stop the spread of it. Almost all the health care sectors are focusing on treating the symptoms and decrease mortality. Although many repurposed drugs have succeeded to alleviate symptoms and decrease the infection burden. Inhibition of excessive inflammatory response may be an adjunct for treating COVID-19, so in some countries, addition an adjuvant corticosteroid therapy to standard antiviral treatment. Literature does not currently provide convulsive evidence for or against the use of corticosteroids in the treatment of COVID-19 patients. Typically, Corticosteroids are used to treat severe acute respiratory infections of viral etiology because of their anti-inflammatory effect. Nevertheless, when use corticosteroid, the neutrophil count is increased, other lymphocyte/leucocytes subsets are decreased. So, the monocyte -to- lymphocyte ratio (MLR) take same direction in decreasing whereas neutrophil-to-lymphocyte ratio (NLR) abnormally increased which leads to predict a worse prognosis and wrong intervention. A need to monitor the prognosis of the disease using a specific marker is feasible economic wise and health wise, as seeing the prognosis of COVID-19 give us the ability to take an action in managing the upcoming issues and precede the virus one step ahead. So, in this review article, we will discuss all available evidences regarding the prognostication performances of MLR and NLR in discrimination bacterial from viral infections, clinical infectious from clinical non-infectious cases, and COVID-19 from other viral infections. Also, in this review article, we will focus on the Corticosteroid and Mal-Nutrition-Associated Overestimation impacts on the performance potentials of MLR vs NLR for prog