Evaluation of the Diagnostic and Predictive Significance of Postoperative C-Reactive Protein to Transferrin or Albumin Ratio in Identifying Septic Events Following Major Abdominal Surgery

<b>Background/Objectives:</b> Postoperative septic events represent a major paramevter of morbidity and mortality following major abdominal surgery. Early identification and prediction can have a major impact on clinical management, reduction of hospitalization costs, and restriction of irrational use of antibiotics. For this purpose, two novel biomarkers (C-reactive protein to albumin or transferrin ratios, CAR and CTR, respectively) were evaluated. <b>Methods</b>: A combined retrospective and prospective study of 200 patients who underwent elective or emergency open abdominal surgery was performed. Patient demographics, emergency status, type of operation, and white blood cell (WBC) count, serum albumin (ALB), serum transferrin (TRF), and CAR-CTR were evaluated. Multiple-way ANOVA was utilized. Multiparametric and logistic regression analyses were performed for each confounder. Receiver operating characteristic (ROC) curve analysis and corresponding diagrams of sensitivity vs 1-specificity were applied for CAR and CTR in postoperative days 2 and 3. <b>Results</b>: WBC number had no predictive significance in septic event identification (<i>p</i> = 0.461), while postoperative CAR, CTR, ALB, TRF, BMI, and emergency status were significantly correlated (<i>p</i> < 0.001). At postoperative day 2, a CTR of 9.48 and a CAR of 4.14 have 75.9% and 70.4% specificity and 86% and 87.7% sensitivity, respectively. At postoperative day 3, a CTR of 8.89 and a CAR of 4.25 have 74.1% and 79.6% specificity and 87.7% and 86% sensitivity, respectively. <b>Conclusions</b>: Early identification of postoperative septic events may significantly facilitate decreasing postoperative morbidity and mortality. Both CAR and CTR displayed significant predictive ability in identifying patients prone to developing postoperative septic events, highlighting their significance in everyday clinical practice.