Presepsin as a Novel Biomarker in Abdominal Sepsis: Diagnostic Accuracy and Prognostic Implications

Background/Objectives: Abdominal sepsis remains a major contributor to morbidity and mortality among surgical and critically ill patients worldwide. Timely diagnosis is frequently hindered by the overlapping clinical and biochemical features of postoperative inflammatory responses and evolving intra-abdominal infections, which may resemble systemic sepsis. Conventional biomarkers, including C-reactive protein (CRP) and procalcitonin (PCT), are widely implemented in clinical practice but demonstrate suboptimal specificity in differentiating infectious from sterile inflammatory conditions in the early postoperative phase. Presepsin (soluble CD14 subtype, sCD14-ST), a circulating fragment released during monocyte–macrophage activation in response to bacterial endotoxins, has emerged as a biomarker reflecting innate immune engagement. This review aims to critically evaluate the current evidence regarding the diagnostic accuracy, prognostic relevance, and potential clinical role of presepsin in abdominal sepsis. Methods: A comprehensive narrative review of the biomedical literature was performed using MEDLINE (via PubMed) and supplementary academic sources. Studies assessing the diagnostic performance, prognostic associations, and clinical applicability of presepsin in abdominal infections, postoperative infectious complications, and sepsis were systematically examined. Where available, comparative analyses with established biomarkers such as CRP and PCT were evaluated to contextualize its incremental value within existing diagnostic frameworks. Results: The accumulated evidence indicates that presepsin concentrations increase early during bacterial infections and correlate with validated severity indices, organ dysfunction scores, and mortality outcomes. Across multiple surgical and intensive care settings, presepsin demonstrated moderate-to-high diagnostic performance, frequently comparable to and occasionally exceeding that of traditional inflammatory biomarkers, particularly in distinguishing septic from non-septic inflammatory states. Moreover, dynamic changes in circulating levels appear to provide additional prognostic information and may support longitudinal clinical assessment. Nonetheless, substantial heterogeneity in study design, patient populations, sampling strategies, and reported cut-off values limits direct cross-study comparability and constrains definitive clinical recommendations. Conclusions: Presepsin represents a biologically plausible and clinically promising biomarker for the early identification and risk stratification of abdominal sepsis. Although current findings are encouraging, further large-scale, methodologically standardized prospective investigations are required to define optimal diagnostic thresholds and to clarify its role within multimodal biomarker strategies in contemporary sepsis management.