Can we predict the severity of COVID-19 with a routine blood test?

Zeng, Furong; Li, Linfeng; Zeng, Jiling; Deng, Yuhao; Huang, Huining; Chen, Bin; Deng, Guangtong

INTRODUCTION The ongoing worldwide pandemic of Coronavirus Disease 2019 (COVID-19) has posed a huge threat to global public health. However, whether routine blood test could be used to monitor and predict the severity and prognosis of COVID-19 has never been comprehensively investigated. OBJECTIVES To provide an overview of the association of markers in routine blood test with the severity of COVID-19. METHODS PubMed, Embase, Cochrane Library, Wanfang and CNKI database were searched to identify studies reporting the markers in the routine blood test with the severity of COVID-19 until March 20, 2020. STATA software was used for the meta- analysis. RESULTS A total of 15 studies with 3090 COVID-19 patients were included in this analysis. Patients in non-severe group had fewer white blood cells (WBC) (WMD = -0.85 [109/L], 95% CI = [-1.54, -0.16], P = 0.02) and neutrophils (WMD = -1.57 [109/L], 95% CI = [-2.60, -0.54], P = 0.003), more lymphocytes (WMD = 0.29 [109/L], 95% CI = [0.22, 0.36], P < 0.001) and platelets (WMD = 19.05 [109/L], 95% CI = [3.04, 35.06], P = 0.02), and lower neutrophil-to-lymphocyte ratio (NLR) level (WMD = -2.48, 95% CI = [-3.81, -1.15], P < 0.001), compared with those in severe group. There was no statistical difference in monocytes (WMD = 0.01 [109/L], 95% CI = [-0.01, 0.03], P = 0.029) between these two groups. Sensitivity analysis and meta-analysis based on standard mean difference (SMD) did not change the conclusions about neutrophils, lymphocytes and NLR while the results were inconsistent in WBC and platelets. CONCLUSIONS Severe patients had more neutrophils, higher NLR level, and fewer lymphocytes than non-severe patients with COVID-19. Measurement of these markers might assist clinicians to monitor and predict the severity and prognosis of COVID-19.