DIAGNOSTIC PERFORMANCE OF THE LRINEC SCORE FOR EARLY DIFFERENTIATION BETWEEN CELLULITIS AND NECROTIZING FASCIITIS: A PROSPECTIVE COMPARATIVE STUDY

Abstract

Background: Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection with high mortality if diagnosis is delayed. Clinical overlap with cellulitis makes early distinction difficult. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score, based on routine laboratory parameters, has been proposed as a diagnostic tool for differentiating NF from cellulitis.

Objective: To evaluate the diagnostic accuracy of the LRINEC score in distinguishing NF from cellulitis in patients presenting with severe soft tissue infections.

Methods: This prospective observational study included 150 patients with suspected severe soft tissue infections admitted to a tertiary care center between January 2023 and June 2024. All patients underwent baseline laboratory evaluation to calculate LRINEC scores. Final diagnosis of NF was confirmed by operative findings and histopathology, while cellulitis was diagnosed clinically and by response to antibiotics. Diagnostic performance of the LRINEC score was assessed using sensitivity, specificity, predictive values, and receiver operating characteristic (ROC) analysis.

Results: Of 150 patients, 42 (28%) were confirmed to have NF, and 108 (72%) had cellulitis. The mean LRINEC score was significantly higher in NF (8.1 ± 2.3) compared to cellulitis (3.9 ± 1.8, p < 0.001). A cutoff ≥6 yielded sensitivity of 78.5%, specificity of 84.2%, positive predictive value 70.2%, and negative predictive value 89.1%. ROC analysis demonstrated an area under the curve (AUC) of 0.87, indicating excellent diagnostic accuracy.

Conclusion: The LRINEC score is a valuable adjunct for early differentiation of necrotizing fasciitis from cellulitis. A score ≥6 provides high specificity and acceptable sensitivity, making it a useful tool for risk stratification. However, it should not replace clinical judgment or surgical exploration, especially in equivocal cases. Integration of LRINEC into clinical protocols may facilitate earlier intervention and improve patient outcomes.