Serum Procalcitonin Levels as Predictors of Clinical Outcomes in Patients with Secondary Peritonitis

Introduction: Secondary peritonitis remains a formidable challenge in emergency general surgery, with significant morbidity and mortality. Despite advances in surgical technique, postoperative complications—particularly surgical site infections (SSIs) and respiratory failure—remain common. This study examines the prognostic utility of serum procalcitonin (PCT) and C-reactive protein (CRP) as biochemical markers for risk stratification and prediction of clinical outcomes in patients with secondary peritonitis. Materials and Methods: A prospective observational study was conducted from February 2023 to April 2024, including 95 patients diagnosed with secondary perforation peritonitis. Serum PCT and CRP concentrations were measured at admission and 48–72 hours postoperatively. Patients were followed for 30 days. The primary clinical endpoints were ICU admission, mechanical ventilation, prolonged hospital stay, SSI, and 30-day mortality. Results: The study cohort had an overall mortality rate of 13.7%. Statistical analysis showed that admission PCT levels > 1.28 ng/mL were a highly significant predictor of non-survival. Furthermore, a postoperative PCT threshold of >0.5 ng/mL at 48 hours was strongly correlated with the subsequent development of SSIs. Although elevated CRP levels were associated with adverse clinical trajectories, PCT demonstrated superior discriminative power for specific outcomes. Conclusion: Serum PCT and CRP are robust predictors of mortality and morbidity in secondary peritonitis. Specifically, a PCT level > 1.28 ng/mL at admission provides critical prognostic information about survival, whereas postoperative PCT levels > 0.5 ng/mL facilitate early identification of SSI risk. These findings suggest that incorporating serial biomarker monitoring into clinical workflows can enhance risk-based decision-making. Larger multicenter trials are warranted to validate these thresholds.