The changes in blood coagulation, especially disseminated intravascular coagulation (DIC), which is common in critical diseases, should also been paid enough attention [61], [62], [63], [64]. Severe patients may exhibit blood coagulation disorders, including increased D-dimer, prolonged PT and shortened APTT, which is consistent with reports [62], [63]. D-dimer is associated with the severity of COVID-19 [65]. Fibrinogen can be significantly increased in the early stages of severe patients, but notably decreased in the later stages, this may be the reason why serious people are more likely to suffer from cerebrovascular disease [66], [67]. Bleeding and coagulation dysfunction and even DIC combined with COVID-19 is a process of dynamic change. Monitoring the blood coagulation function of patients is beneficial to the early diagnosis, prevention and treatment of the disease. In addition, The combined detection of IL-6 and D-dimer had important clinical value for early prediction of the severity of COVID-19 patients due to its high sensitivity and specificity [68].