Neutrophil to Lymphocyte Ratio (NLR) and Derived NLR Combination: A Cost-effective Predictor of Moderate to Severe COVID-19 Progression

Inflammation is an essential contributor to Coronavirus disease 2019 (COVID-19). In this regard, finding a prognostic indicator is valuable because the treatment will be more effective if critical patients with high inflammation are diagnosed earlier. We aimed to evaluate some hematologic markers for COVID-19 and assess their association with the severity of the disease. A total of 154 COVID-19 patients were laboratory-confirmed and admitted to Imam Khomeini Hospital Complex, Tehran, Iran, from February 12, 2020, to April 4, 2020, and 55 healthy individuals were enrolled in the study. The severity of the patients' illnesses was classified into three subgroups according to the types of oxygen therapies (moderate (61), severe (28), and critical (43)) and examined the different ratios of total white blood cell (WBC) count, neutrophil to lymphocyte ratio (NLR), platelet to monocyte ratio (PLR), macrophage to lymphocyte ratio (MLR), derived NLR ratio (dNLR), and some biochemical tests. COVID-19 patients had higher levels of NLR, MLR, PLR, and dNLR than healthy subjects. receiver operating characteristic (ROC) analysis of the curve revealed that NLR and dNLR had a high diagnostic value to differentiate COVID-19 patients from healthy subjects (area under the curve [AUC]=0.923 and 0.910, respectively) and predict mortality (AUC=0.726 and 0.735, respectively). NLR and dNLR may be reliable markers to evaluate the severity of COVID-19. NLR and dNLR had a high diagnostic value for differentiating COVID-19 patients from healthy subjects, and they could predict the severity and outcome of the disease.