INTRODUCTION
The outbreak of unexplained pneumonia in Wuhan, China in December 2019 rapidly spread and attracted worldwide attention(1). On 30 January 2020, the disease caused by the SARS-CoV-2 virus was named coronavirus disease 2019 (COVID-19), and a global pandemic was declared by the World Health Organisation on 11 March 2020 (2, 3).
Biomarkers of inflammation in the blood such as white blood cell (WBC) count, NLR, PLR, and serum CRP have been investigated as independent predictors of the prognosis of inflammatory diseases (4, 5).
NLR is easily calculated from routine blood test by dividing the absolute neutrophil count by the absolute lymphocyte count, and is important in showing the general inflammatory status of the patient (6).
Recent research has shown that severe COVID-19 cases tend to have higher NLR (7).
CRP is an acute inflammatory protein, which increases up to 1000-fold in regions of infection and inflammation. CRP is a routinely measured inflammatory marker, which has been reported to be increased in the majority of COVID-19 patients and to be associated with disease severity (7-9).
A confirmed diagnosis of COVID-19 infection requires PCR identification of viral nucleic acid and lung imaging (10). Most patients have lung imaging results indicating bilateral pulmonary involvement with parenchymal ground-glass appearance and consolidated pulmonary opacities, sometimes with a rounded morphology and peripheral lung distribution. There is a notable absence of lung cavitation, discrete pulmonary nodules, pleural effusions, and lymphadenopathy (10).
The aim of this study was to determine whether or not there was a correlation between the CRP value, NLR, and PLR, and the lung involvement severity score according to the thoracic CT findings of patients who developed COVID-19 pneumonia.