CALCA and infection: When comparing the comparative predictive abilities of the three models using Kaplan-Meier survival analysis, the study reported that the combination of PCT with CRP and WBC (PCT > 4.15 ng/ml + CRP > 22.03 mg/l + WBC > 15.3 × 103/μl) on POD 3 offers the best predictive value for early postoperative infection compared to using PCT alone or PCT combined with CRP or WBC (Figure 2).