Diagnostic and Prognostic Value of Laboratory Risk Indicator for Necrotizing Fasciitis Score

Necrotizing fasciitis (NF) is a lethal soft tissue infection involving skin and subcutaneous tissue with significant morbidity and mortality.

To validate the diagnostic and prognostic role of the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system for NF in patients who present with soft tissue infections.

The study was conducted on 100 patients who presented with soft tissue infections. Based on the histopathological findings, they were divided into NF and non-necrotizing soft tissue infection groups. Patients were clinically assessed. The lab parameters were assessed and the LRINEC score was calculated. Patients were stratified based on score and grouped into low, intermediate, and high risk. For patients who went into sepsis, the death rate and length of hospital stay, including ICU, were noted based on the scoring system.

In our study, the diagnostic role of LRINEC score ≥ 6 had a sensitivity of 85.7% and specificity of 62.7%, and score ≥ 8 had a sensitivity of 67.3% and specificity of 82.3% with a positive predictive value (PPV) of 78.5 and negative predictive value (NPV) of 72.4, of which 8 is a better cut-off as a diagnostic criterion. The area under the curve was found to be 0.835. To predict the prognostic role, a cut-off value was calculated from the receiver operating characteristic curves of both mortality and sepsis patients in relation to the LRINEC score of 9. With the LRINEC score cut-off as 9, with mortality and sepsis as variables, the sensitivity was 50% and 53.3%, specificity was 94.2% and 91.4%, PPV was 78.9% and 72.7%, and NPV was 81.4% and 82%, respectively.

The LRINEC score is quick, safe, reproducible, noninvasive, cost-effective, and easily calculated, and has high sensitivity and specificity to predict early diagnosis, and it could be used for risk stratification and prognosis of necrotizing soft tissue infections.