sTREM-1 is a potential useful biomarker for exclusion of ongoing infection in patients with secondary peritonitis.

Identification of patients with ongoing abdominal infection after emergency surgery for abdominal sepsis is difficult. The purpose of this study was to evaluate whether plasma and abdominal fluid sTREM-1 levels can adequately select patients with ongoing abdominal infection. In a single center retrospective observational study, plasma and abdominal fluid samples were collected every 24 h for 4 days in patients who underwent an emergency laparotomy for severe secondary peritonitis. Patients after elective esophagus surgery served as controls. sTREM-1 levels were measured with an ELISA. Plasma sTREM-1 levels were not elevated compared to controls. Abdominal fluid sTREM-1 levels were initially high (median (246 [IQR 121-455] pg/ml), and declined 24 h after surgery (P=0.01). On day 2 and 3, patients with ongoing infection had significantly higher abdominal fluid sTREM-1 levels (319 [180-671] and 245 [173-541] pg/ml, respectively) compared to patients without infection (85 [49-306] and 121 [20-196] pg/ml, respectively). sTREM-1 levels were moderately predictive for persistent infection but had a high negative predictive value (0.86 (95% CI 0.69-0.94) below a cut-off level of 160 pg/ml. In clinical practice, abdominal fluid sTREM-1 levels may be useful for exclusion but not detection of ongoing abdominal infection after surgery for secondary peritonitis.