EVALUATING THE DIAGNOSTIC VALUE OF PROCALCITONIN AND C-REACTIVE PROTEIN IN EARLY SEPSIS DETECTION: IMPLICATIONS FOR IMMUNE FUNCTION, RECOVERY, AND PHYSICAL PERFORMANCE

Abstract

Background: Sepsis is a life-threatening condition characterized by dysregulated immune responses and systemic inflammation, leading to multiorgan dysfunction and impaired physical recovery. Early diagnosis and timely intervention are crucial for improving survival rates, optimizing rehabilitation, and maintaining functional capacity in critically ill patients. Procalcitonin (PCT) and C-reactive protein (CRP) are well-established inflammatory biomarkers, but their diagnostic accuracy and clinical utility in sepsis detection remain areas of active investigation. This study evaluates the application value of PCT and CRP levels in the early diagnosis of sepsis, with implications for critical care management, immune function, and post-sepsis rehabilitation in physically active individuals. Methods: A total of 302 critically ill patients admitted to the Intensive Care Unit (ICU) between February 1, 2020, and February 1, 2023, were included in this study. Patients were classified into three groups based on sepsis diagnostic criteria: sepsis group (n=102), septic shock group (n=87), and non-sepsis (control) group (n=113). Serum PCT levels were measured using enzyme-linked fluorescence analysis, while CRP concentrations were determined using fluorescence immunoassay quantification. The diagnostic performance of PCT and CRP was assessed through receiver operating characteristic (ROC) curve analysis, calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy. Results: No significant differences were observed among the three groups in age, gender, APACHE II scores, or ICU length of stay (P>0.05). However, ISS scores and hospital mortality rates were significantly higher in the sepsis and septic shock groups (P<0.05). PCT levels in the sepsis group (6.01±3.97 µg/L) were significantly higher than in the control group (1.67±0.92 µg/L, P<0.05), while CRP concentrations were also elevated in the sepsis group (34.90±15.70 mg/L) compared to controls (12.40±7.97 mg/L, P<0.05). The septic shock group exhibited the highest CRP levels (148.28±32.03 mg/L, P<0.05). The positive detection rates for PCT and CRP were significantly higher in septic shock (PCT: 93.1%, CRP: 90.8%) and sepsis patients (PCT: 80.4%, CRP: 79.4%) compared to controls (PCT: 29.2%, CRP: 25.7%) (X² =107.702, P<0.05). The combined PCT and CRP assay demonstrated superior diagnostic performance compared to either marker alone, with higher sensitivity (84.7%), specificity (87.6%), PPV (92.0%), NPV (77.3%), and overall accuracy (85.8%). ROC curve analysis showed an area under the curve (AUC) of 0.871-0.970 for the combined markers, significantly outperforming PCT alone (AUC = 0.850) and CRP alone (AUC = 0.814) (P<0.05). Conclusion: Serum PCT and CRP levels serve as reliable biomarkers for assessing sepsis severity, with higher concentrations correlating with more severe cases. The combined measurement of PCT and CRP significantly enhances early diagnostic accuracy, surpassing the performance of individual markers. These findings have critical implications for improving early sepsis detection, guiding timely interventions, and optimizing post-sepsis recovery protocols, particularly in patients requiring physical rehabilitation and functional restoration. Future research should explore the role of inflammatory biomarker monitoring in sports medicine and rehabilitation to mitigate the long-term impact of post-sepsis immune dysregulation and physical deconditioning.