E-Book 2nd Congress

  • Neutrophil to lymphocyte ratio in COVID-19 prognosis
  • Roqaye Karimi,1,* Alireza Soleimani,2 Mahin Behzadifard,3 Amir Atashi,4
    1. Department of Hematology and Cell Therapy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
    2. Student Research Committee Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
    3. Dezful University of Medical Sciences, Dezful, Iran.
    4. Stem Cell and Tissue Engineering Research Center, Shahroud University of Medical Sciences, Shahroud, Iran.


  • Introduction: Coronavirus disease 2019 (COVID-19) is a global public crisis. Clinical presentation can range from the absence of symptoms to multiple organ failure and death. Several management guidelines were introduced, however, their effectiveness is still debated. Therefore, the presence of prognostic factors is necessary to predict which patients require more aggressive treatments.
  • Methods: Considering the wide spectrum of possible clinical manifestations and the potential variation during the evolution of the disease, the diagnosis of hyper-inflammatory state is the first step in identifying patients so that we can treat them in the most appropriate way according to the stage of the disease. Circulating biomarkers of inflammation play a predominant role in this regard. A simple blood test would be required to assess the inflammatory status and to help predict the outcome of patients. Apart from the well-known biomarkers of inflammation, such as C-reactive protein (CRP), serum amyloid A, interleukin (IL)-6, procalcitonin (PCT), the parameter of neutrophil to lymphocyte ratio (NLR) have been recently suggested to predict the disease severity or prognosis of COVID-19 patients. Specifically, NLR is a simple ratio obtained by dividing the absolute count of neutrophils from lymphocytes. Notably, neutrophils and lymphocytes are closely related to the pathophysiology of COVID-19. A number of recently studies have reported that neutrophilia, lymphopenia, and NLR increase are strongly associated with disease severity and mortality from COVID-19 and can be useful in distinguishing severe from non-severe cases of COVID-19 patients. In 2020, Qin C et al. reported that peripheral blood T-lymphocyte levels were significantly reduced, while neutrophil levels were augmented in severe cases of COVID-19 compared to mild cases of COVID-19. Another report done in 2020 showed that the severity rate in patients with elevated NLR was higher, but the recovery rate was lower than the cases with lower NLRs.
  • Results: All these data show that NLR is a reliable indicator to determine disease severity in COVID-19.
  • Conclusion: These findings provide evidence that NLR is a cheap and useful prognostic marker in distinguishing severe from non-severe patients with COVID-19.
  • Keywords: Coronavirus disease 2019 (COVID-19), Prognostic, Neutrophil to lymphocyte ratio (NLR)