Objective To determine the diagnostic and assessment value of soluble urokinase plasminogen activator receptor (suPAR) level in septic patients.Methods Totally 82 septic patients in the Department of Intensive Care Unit of The First Affiliated Hospital,Sun Yat-Sen University were prospectively analyzed from June 2013 to March 2014.Another 29 patients with systemic inflammatory response syndrome (SIRS) and 15 healthy subjects served as controls.Septic patients were divided into sepsis group (n =27),severe sepsis group (n =27) and septic shock group (n =28) according to the severity,and there was no significant difference in age and sex among these groups.Measurement of plasma suPAR,serum procalcitonin (PCT) and C-reactive protein (CRP) levels,and calculation of acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) and sequential organ failure assessment (SOFA) score were performed.Comparison of group differences for continuous variables was done by oneway ANOVA or nonparametric Kruskal-Wallis test.Spearman rank correlation analysis was applied to establish the relation between variables.Receiver operating characteristics (ROC) curve was created and area under curve (AUC) was calculated to determine the diagnostic value of these variables in sepsis.Results The levels of plasma suPAR in SIRS group,sepsis group,severe sepsis group,septic shock group,and healthy control group were (8.22±0.61),(11.45±1.12),(12.99±1.28),(15.75± 1.23) and (4.65 ±0.30) ng/mL,respectively.Plasma suPAR levels in SIRS group and sepsis group were higher than that in healthy control group (P ＜ 0.01),and elevated plasma suPAR was accompanied by increased severity of sepsis (P ＜ 0.05).PCT levels of sepsis group (17.66 ± 8.42) ng/mL,severe sepsis group (9.67 ±3.56) ng/mL and septic shock group (29.19 ± 10.78) ng/mL were greater than that in SIRS group (1.10 ± 0.78) ng/mL,P ＜ 0.01.CRP levels elevated in all groups,but there were no significant differences among them.When suPAR and CRP were applied to distinguishing sepsis from SIRS,the AUC values from suPAR and combination of suPAR and PCT were 0.817 (P ＜ 0.01,95 ％ CI:0.714-0.921) and 0.927 (P＜0.01,95％ CI:0.870-0.985),respectively.Using9.52 ng/mL suPAR as the best cut-off to distinguish sepsis from SIRS,there were 71.93％ sensitivity and 95.46％ specificity.The levels of plasma suPAR positively correlated with PCT levels (r =0.326),APACHE Ⅱ score (r =0.492) and SOFA score (r =0.386),P ＜ 0.01.Conclusions Plasma suPAR levels significantly elevated in septic patients and correlated with the severity of sepsis.Sepsis and SIRS may be discerned by plasma suPAR levels.Joint use of suPAR and PCT could greatly increase the specificity of diagnosis of sepsis.