Comment on ‘‘Can the neutrophil/lymphocyte ratio (NLR) have a role in the diagnosis of coronavirus 2019 disease (COVID-19)?’’

Abstract

We read with great interest the article "Can the neutrophil/lymphocyte ratio (NLR) have a role in the diagnosis of coronavirus 2019 disease (COVID-19)?" by Nalbant et al 1 . They aimed to evaluate the role of neutrophil/lymphocyte ratio (NLR), an inflammation marker in the diagnosis of COVID-19. They concluded that NLR is an independent predictor for the diagnosis of COVID-19. First of all, We congratulate the authors for their invaluable contribution to the literatüre. However, we think that some points should be discussed about the study.White blood cell count, CRP, and immature granulocyte are useful inflammatory biomarkers in clinical practice 2,3 . An easily measurable laboratory marker is used to evaluate systemic inflammation, particularly the WBC subtypes NLR and platelet/lymphocyte ratio (PLR) 4 . However, these parameters are affected by many factors such as acute coronary syndromes, local or systemic infection, previous history of infection, inflammatory diseases, renal or hepatic dysfunction and known malignancy [2][3][4][5] . For these reasons, it would be better if the authors had mentioned these factors.It is well known that some drug use, such as corticosteroids, can increase neutrophils and decrease lymphocytes.