Introduction
The novel coronavirus (SARS-CoV-2) that causes novel coronavirus pneumonia (COVID-19) is the third fatal coronavirus. It first emerged in December 2019 in China(1). The most common symptoms are fever, dry cough, and exhaustion. Dyspnea and/or hypoxemia are common 1 week after the onset of symptoms in severe patients. Acute respiratory distress syndrome (ARDS), septic shock, difficult-to-correct metabolic acidosis, coagulation deficiency, and multiple organ failure can all occur rapidly in serious cases (2, 3). Patients with mild clinical manifestations do not require hospitalization at first, but they may develop respiratory symptoms by the second week, so all patients should be closely monitored(4). According to the World Health Organization (WHO), approximately 80 percent of sick people have mild to moderate infections (including those with or without pneumonia), 13.8 percent have serious infections, and 6.1 percent have critical illness (4). The prognosis of the disease varies depending on patient specialties. As a result, identifying and diagnosing serious or critical patients is important. Hematological analysis is the most commonly conducted procedure in clinics, and complete blood count (CBC) findings are the first things that physicians want to see in nearly all labs, outpatient and inpatient clinics. In the current novel coronavirus pandemic, it would be very helpful for clinicians to make a rational allocation of medical resources if the most routine and affordable laboratory tests can be used to provide clinicians with convenient assistance in assessing the patient’s condition. Early clinical intervention is expected to minimize patient mortality(4). It has been shown that the total number of peripheral white blood cells is normal or the number of lymphocytes is decreased in patients in the early stage of COVID-19. Tan et al. reported that Lymphocyte percent was inversely linked to patient severity and prognosis, and could be used to predict COVID-19 patient’s severity and prognosis (5). This means that patients with SARS-CoV-2 infections will experience changes in their peripheral blood. These adjustments can hold clues or provide guidance for COVID-19 patients’ diagnosis, care, and prognosis. The aim of this study was to correlate CBC parameters and ferritin levels at the time of diagnosis with the prognosis of patients hospitalized due to Covid-19.