Evaluation of laboratory risk indicator for necrotizing fasciitis score as an early diagnostic tool for necrotizing fasciitis: a prospective observational study.

Introduction: From its historical identification to modern times with advancements in management modalities globally, the mortality of necrotizing fasciitis (NF) is high ranging from 19 to 30% for all affected sites. Although many diagnostic adjuncts have been developed to assist with the prompt and accurate diagnosis of NF, the primary diagnosis is still based on high clinical suspicion. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score was developed as a tool for distinguishing NF from other soft tissue infections. The main objective of this study is to evaluate LRINEC as a tool for early diagnosis of NF and differentiating it from other soft tissue infections like cellulitis.

Methods: This is a single-centered, prospective observational study. Patients presenting with soft tissue infections of the limbs to the emergency department from November 2020 to October 2021 were included in this study. The clinical findings and blood parameters for the LRINEC score were collected and the score was calculated. Based on clinical suspicion of NF, patients underwent debridement and had a tissue biopsy to confirm the diagnosis. The data obtained was analyzed using SPSS version 24 and MS Excel. The AUC curve was used to calculate a cutoff, sensitivity, specificity, positive predictive value, and negative predictive values for the LRINEC score based on our study.

Results: Forty-five patients with 28 males and 17 females were included. The average age was 53.667 years within a range of 19-79 years. Among them 44.4% of the patients had NF and 66.6% had other minor forms of soft tissue infections. The ROC curve obtained a cutoff value of greater than or equal to 6, with an AUC of 0.751. At this cut of value study showed a sensitivity of 85% with a specificity of 52%. Similarly, positive predictive value was found to be 58.62%, negative predictive values of 81.25%, and overall accuracy of 66.67% in early diagnosis of NF.

Conclusion: In conclusion, our study showed that the LRINEC score can be a reliable tool for the early diagnosis of NF in an ED setting. This scoring system is best to be used to rule out NF.