Can we predict the severity of coronavirus disease 2019 with a routine blood test?

ABSTRACT

INTRODUCTION: The ongoing worldwide pandemic of coronavirus disease 2019 (COVID­19) has posed a huge threat to global public health. However, the issue as to whether routine blood tests could be used to monitor and predict the severity and prognosis of COVID­19 has not been comprehensively investigated so far. OBJECTIVES: This study aimed to provide an overview of the association of markers in the routine blood test with the severity of COVID­19. METHODS: PubMed, Embase, Cochrane Library, Wanfang, and China National Knowledge Infrastructure (CNKI) databases were searched to identify studies reporting data on markers in the routine blood test and the severity of COVID­19, published until March 20, 2020. The STATA software was used for meta­analysis. RESULTS: A total of 15 studies with 3090 patients with COVID­19 were included in this analysis. Patients in the nonsevere group, compared with those in the severe group, had lower counts of white blood cells (weighted mean difference [WMD], -0.85 [×109/l]; 95% CI, -1.54 to -0.16; P = 0.02) and neutrophils (WMD, -1.57 [×109/l]; 95% CI, -2.6 to -0.54; P = 0.003), greater counts of 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 a lower neutrophil­to­lymphocyte (NLR) ratio (WMD, -2.48; 95% CI, -3.81 to -1.15; P <0.001). There was no difference in the monocyte count (WMD, 0.01 [×109/l]; 95% CI, -0.01 to 0.03; P = 0.029) between these 2 groups. Sensitivity analysis and meta­analysis based on standard mean difference did not change the conclusions regarding neutrophils, lymphocytes, and NLR, but yielded inconsistent results for white blood cells 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.