Screening and combining serum biomarkers to improve their diagnostic performance in the detection of intestinal barrier dysfunction in patients after major abdominal surgery

Background: The aim of this prospective study was to screen and combine effective biomarkers to improve their diagnostic performance in detecting intestinal barrier dysfunction in patients after major abdominal surgery. Methods: Patients undergoing major abdominal surgery were enrolled after signing informed consent in this study. The serum concentrations of alpha-GST, DAO, D-lactate, citrulline and I-FABP were detected 24 hours before and after surgery. The diagnostic performance of five biomarkers on intestinal barrier dysfunction was assessed using logistic regression models and receiver operating characteristic (ROC) curve analyses. Results: Thirty-nine patients with major abdominal surgery were enrolled in and successfully completed this study. ROC analysis revealed that the sensitivities of D-lactate, citrulline and I-FABP were very high (0.91, 0.91 and 1.00, respectively), but the specificities of these biomarkers were less than 0.70. The sensitivity of DAO was very low [0.25; 95% confidence interval (CI), 0.05-0.57], but its specificity was high (0.92; 95% CI, 0.75-0.99). The accuracies of D-lactate and I-FABP were very high, and the areas under the curves (AUCs) of the biomarkers were 0.84 (95% CI, 0.68-0.93) and 0.81 (95% CI, 0.65-0.92), respectively. Different combinations of five biomarkers were also analysed. The sensitivity, specificity and AUC values of the combination of I-FABP, citrulline and D-lactate were 1.00, 0.74 and 0.89, respectively. These results were similar to those derived from the combination of alpha-GST, DAO, D-lactate, citrulline and I-FABP (P=1.000). Conclusions: The combination of serum D-lactic acid, citrulline and I-FABP greatly improved the diagnostic performance for identifying intestinal barrier dysfunction in patients after major abdominal surgery.