Abstract： Objective:To evaluate the clinical value of new coagulation biomarkers including soluble thrombomodulin (sTM) and tissue plasminogen activator inhibitor complex (t-PAI·C) for the diagnosis and prognosis of sepsis in children.Methods:The prospective observational study enrolled 59 children who were diagnosed with sepsis including severe sepsis and septic shock in the Department of Pediatric Critical Care Medicine of Shanghai Children′s Medical Center affiliated to the Medical College of Shanghai Jiao Tong University from June 2019 to June 2021. The sTM, t-PAI·C and conventional coagulation tests were detected on illness day one of sepsis. Twenty healthy children were selected as the control group, and the above parameters were detected on the day of inclusion. Children with sepsis were divided into survival group and non-survival group according to prognosis at discharge. Baseline comparisons between groups were performed using Mann-Whitney U test. Multivariate Logistic regression analysis was used to evaluate the risk factors for the diagnosis and prognosis of sepsis in children. Receiver operating characteristic (ROC) curve was conducted to evaluate the predictive values of above variables for the diagnosis and prognosis of sepsis in children. Results:The sepsis group included 59 patients (39 boys and 20 girls), aged 61(22, 136)months. There were 44 patients in the survival group and 15 patients in the non-survival group, respectively. The control group consisted of 20 boys, aged 107 (94,122) months. Patients in the sepsis group had higher sTM and t-PAI·C ((12 (9, 17)×10 3vs. 9(8, 10)×10 3 TU/L, 10(6, 22) vs. 2 (1, 3) μg/L, Z=-2.15, -6.05, both P<0.05) compared with children in the control group. The t-PAI·C was superior to sTM for the diagnosis of sepsis. The areas under the curve (AUC) of t-PAI·C and sTM for the diagnosis of sepsis were 0.95 and 0.66, respectively, and the optimal cut-off value were 3 μg/L and 12×10 3 TU/L, respectively. Patients in the survival group had lower sTM (10 (8, 14)×10 3vs. 17 (11, 36)×10 3 TU/L, Z=-2.73, P=0.006) than those in the non-survival group. Logistic regression analysis showed that sTM was a risk factor for death at discharge ( OR=1.14, 95% CI 1.04-1.27, P=0.006). The AUC of sTM and t-PAI·C for predicting death at discharge were 0.74 and 0.62, respectively, and the optimal cut-off values were 13×10 3 TU/L and 6 μg/L, respectively. The AUC of sTM combined with platelet counts for predicting death at discharge was 0.89, which was superior to sTM and t-PAI·C. Conclusion:The sTM and t-PAI·C had clinical application values in diagnosing and predicting prognosis in pediatric sepsis.