Abstract: Objective To explore the association of inflammatory markers of interleukin-6 （IL-6）, serum amyloid A （SAA）, procalcitonin （PCT）, and C-reactive protein （CRP） with the severity of coronavirus disease 2019 （COVID-19）. Methods Clinical data of patients with COVID-19 from January 2020 to February 2020 in a hospital in Fuyang City, Anhui Province were collected for clinical analysis. Serum levels of IL-6, SAA, PCT, and CRP were compared between the severe and mild cases of COVID-19. The value of serum IL-6, SAA, PCT, and CRP in the identification of mild and severe cases of COVID-19 was explored, and their association with the severity of the COVID-19 were evaluated. Results A total of 70 patients with COVID-19 who met the criteria of this study were enrolled, including 19 cases of severe COVID-19 （severe group） and 51 cases of mild one （mild group）. Serum levels of IL-6, SAA, and CRP in the severe group were higher than those in the mild group （P<0. 05 for all）. The area under the curve of serum IL-6, SAA, and CRP combined to identify the mild and severe COVID-19 cases was 0. 817, which was greater than the single identification of each index. The optimal sensitivity of the combined identification was 78. 93% and the specificity was 80. 39%. The levels of serum IL-6 and CRP were positively correlated with the severity of the COVID-19 （P<0. 05）. Conclusion The serum levels of IL-6 and CRP are abnormally high in patients with severe COVID-19, and positively correlated with the severity of COVID-19, which is helpful to distinguish the severity of COVID-19.

Key words: COVID-19, Inflammatory markers, Interleukin-6, Amyloid A, Procalcitonin, C-reactive protein