Abstract： Objective To investigate the value of the concentration of D-dimer in predicting 28-day mortality of sepsis patients in emergency department in order to determine its prognostic values.Methods A prospective study was conducted.A total of 766 sepsis patients treated in the emergency department of Beijing Chaoyang Hospital of the Capital Medical University from October 2009 to July 2010 were enrolled,and admission blood samples were obtained for D-dimer measurement(solid phase immune chromatography).A variety of clinical and laboratory variables were recorded.With 28 days as end point,the D-dimer levels,acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ)score,and simplify acute physiology score Ⅱ(SAPS Ⅱ)were compared respectively between survivors and non-survivors.The status of each patient was ascertained,and the association between the concentration of D-dimer and 28-day mortality was assessed.Results Two hundred and thirty-three patients died during the 28-day observation period among 766 patients.D-dimer concentration(μg/L)among deceased were significantly higher than those of survivors[1220.0(789.0,1835.0)vs.323.0(158.0,642.0),P＜0.01].The level of D-dimer showed positive correlation with APACHE Ⅱ score and SAPS Ⅱ(r1=0.643,r2=0.632,both P＜0.01).D-dimer concentration had an area under the receiver operating characteristic(ROC)curve(AUC)of 0.880 for predicting 28-day mortality,with 95％ confidence interval(95％ CI)0.855-0.904,P＜0.001; the optimal D-dimer cut point for predicting 28-day mortality was 663.5 μg/L.D-dimer concentration higher than 663.5 μg/L,APACHE Ⅱ score higher than 19.5 and SAPS Ⅱ higher than 39.5 were the independent predictors of 28-day mortality[odds ratio(OR):17.5,15.7,19.6,all P＜0.001].The 28-day mortality(1.4％,12.3％,64.2％),APACHEⅡ score[11(9,13),13(11,16),19(15,22)]and SAPS Ⅱ[24(18,29),31(24,36),40(33,49)]showed statistically significant among D-dimer ＜250.0,250.0-663.5,＞663.5 μg/L three groups(all P ＜0.01).Conclusions D-dimer concentration is an independent predictor of 28-day mortality in patients with sepsis.D-dimer level shows a high predictive value in patients with sepsis,similar to APACHE Ⅱ score and SAPS Ⅱ.It can be helpful in risk stratification in septic patients.