Validation of Diagnostic Scoring Systems in Patients With Clinical Suspicion of Necrotizing Soft Tissue Infection: A Cohort Study.

BACKGROUND: Several scoring systems have been developed and are used to aid in the differentiation of necrotizing soft tissue infection (NSTI) from non-necrotizing soft tissue infections; however, their diagnostic performance in patients with clinical suspicion of NSTI requiring surgical evaluation remains uncertain. STUDY OBJECTIVES: To validate the diagnostic performance of commonly used scoring systems in patients presenting with clinical suspicion of NSTI and requiring surgical evaluation. METHODS: We conducted a retrospective cohort study at a tertiary referral center from September 2018 to December 2022. Adult patients presenting to the emergency department with clinical suspicion of NSTI and subsequent surgical consultation were included. The diagnostic performance of Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC), modified LRINEC (MLRINEC), Japanese LRINEC (J-LRINEC), and SIARI (Site other than lower limb, Immunosuppression, Age, Renal impairment, and Inflammatory markers) scores was evaluated. RESULTS: A total of 359 patients were included, including 214 with NSTI and 145 with non-necrotizing soft tissue infections. Patients with NSTI had significantly higher LRINEC, MLRINEC, and J-LRINEC scores than those without NSTI (all p < 0.001). However, substantial overlap in score distributions was observed between groups. The areas under the curve (AUCs) were 0.663 for LRINEC, 0.693 for MLRINEC, 0.720 for J-LRINEC, and 0.486 for SIARI. Although higher score thresholds demonstrated relatively high specificity, sensitivity remained suboptimal across all evaluated scoring systems. CONCLUSIONS: Although several scoring systems demonstrated statistically significant differences between groups, substantial overlap remained between NSTI and severe non-necrotizing SSTIs, indicating that these scores should not be used as standalone diagnostic tools.