The Kaplan-Meier plot indicates that when combining PCT level > 4.15 ng/ml and CRP level >22.03 mg/l (B) or PCT level >4.15 ng/ml and WBC count >15.3 × 103/μl (C), the predictive value for postoperative infection is higher compared to PCT level >4.15 ng/ml alone (A), with a hazard ratio of 1.93 (95 % CI: 1.03–3.61) (p < 0.05) and 4.83 (95 % CI: 2.00–11.64) (p < 0.05), respectively. Here, CRP is linked to infection.