Neutrophil to lymphocyte ratio, lymphocyte to monocyte ratio and platelet to lymphocyte ratio to predict the severity of COVID-19.

Introduction: In this study, we aimed to investigate and compare the prognostic impacts of C-reactive protein (CRP), white blood cell (WBC) count, neutrophil (NEU)-to-lymphocyte (LYM) ratio (NLR), platelet-to-lymphocyte ratio (PLR), Red Cell Distribution Width (RDW) biomarkers in laboratory-confirmed COVID-19 cases as well as to explore the most useful diagnostic biomarkers and optimal cutoff values in COVID-19 patients.

Methods: A total of 233 patients were admitted to Emergency Department (ED) of Pamukkale University Hospital during two months (March-April 2020) and underwent Sars CoV-2 PCR (Polymerase Chain Reaction), complete blood count (CBC), and CRP tests in sequence due to complaints of COVID-19. The laboratory results and demographic findings were collected from the public health management system retrospectively. The patients with positive Sars CoV-2 PCR test along with hospitalization data were also recorded.

Results: The CRP (p = 0.0001), lactate dehydrogenase (LDH) (p = 0.038), PLR (p = 0.0001) and NLR (p = 0.001) remained significantly higher in the patients with positive Sars CoV-2 PCR test result. By contrast, eosinophil (p = 0.0001), lymphocyte (p = 0.0001), platelet levels (p = 0.0001) were calculated as significantly higher in negative Sars CoV-2 patients.

Conclusion: In the light of the obtained results, the CRP, LDH, PLR and NLR levels remained significantly higher in COVID-19 positive patients, while eosinophil, lymphocyte, and platelet levels were significantly elevated in COVID-19 negative patients.