NLR: A Cost-effective Nomogram to Guide Therapeutic Interventions in COVID-19.

COVID-19 exhibits a non-yet elucidated heterogeneity dominated by mild form of the illness. Nevertheless, mortality is frequent among patients with a delayed innate immune response that suddenly exacerbates during the second week after admission leading to a lethal over inflammation. Therefore, this rapid and unpredictable deterioration requires timely prediction of COVID-19 refractoriness and critical illness. The two biomarkers readily available in routine laboratories, blood lymphocytes and neutrophil counts, are expected to provide an accurate clinical tool to incline reasonable medication and care because lymphopenia marks immune exhaustion while neutrophilia demonstrates the immunological exuberation. Meanwhile, combining the two parameters as a Neutrophil-to-lymphocyte ratio (NLR) helps to constitute a powerful predictive and prognostic nomogram. This scoring tool allows clinicians to stratify COVID-19 severities on admission and guide early interventions to accelerate recovery and shorten the course of disease in order to alleviate the shortage of medical resources and reduce mortality.