Accuracy of the Laboratory Risk Indicator for Necrotizing Fasciitis Score for Diagnosis of Necrotizing Fasciitis

Accuracy of LRINEC Score in Diagnosing Necrotizing Fasciitis

Abstract

Background: Necrotizing fasciitis (NF) is a fast-growing infection that mostly affects the subcutaneous tissue and fascia. The Laboratory risk indicator for necrotizing fasciitis (LRINEC) score was initially presented in 2004. Objective: This study aimed to assess the diagnostic accuracy of the laboratory risk indicator for necrotizing fasciitis (LRINEC) score for the diagnosis of necrotizing fasciitis, taking histopathology as the gold standard. Study Design: Cross-sectional validation study. Settings: General Surgery Department, Sahiwal Teaching Hospital, Sahiwal Pakistan. Duration: Six months from 13 February 2024 to 12 August 2024. Methods: A total of 165 adult cases with suspected necrotizing fasciitis were included. Patients with <48 hours of hospital stay, prior oral antibiotic use, or previous debridement were excluded. Clinical suspicion was based on rapidly spreading erythema with severe pain. LRINEC score, consisting of white blood cells, hemoglobin, sodium, glucose, creatinine, and C-reactive proteins, was calculated. Debridement findings and histopathology confirmed necrotizing fasciitis. Sensitivity, specificity, predictive values, accuracy, and likelihood ratios of LRINEC (≥6) were determined using histopathology as the gold standard. Results: Mean age was 42.4 ± 9.9 years, and 59.4% (n=98) were males. Diabetes mellitus was present in 73.9%. The mean leucocyte count, hemoglobin, serum sodium, blood sugar, and creatinine were 16.6±7.6/mm³, 12.0±2.1 g/dL, 137.4±9.1 mmol/L, 147.3±45.9 mg/dL, and 1.4±0.6 mg/dL, respectively. Necrotizing fasciitis was diagnosed in 39.4% by LRINEC (≥6) and 60% by histopathology. The sensitivity, specificity, and accuracy of LRINEC (≥6) were 55.6%, 84.8%, and 67.3%, respectively. Conclusion: LRINEC score (≥6) showed moderate sensitivity but high specificity for necrotizing fasciitis. It can be useful as an adjunct assessment tool, but histopathology remains the gold standard to make a diagnosis.