How does the Laboratory Risk Indicator for Necrotizing Fasciitis Score Compare to Previously Validated Models in Distinguishing Between Orbital Infectious States?

Purpose: Orbital infectious processes, including necrotizing fasciitis (NF) and orbital cellulitis (OC), often present similarly, although clinical management is individualized for each etiology. Therefore, rapid diagnosis is critical for appropriate therapy and to avoid possible complications. This study was undertaken to compare the efficacy of the Laboratory Risk Indicator for NF score and other established biomarkers in differentiating NF and OC. Methods: Using laboratory results obtained from the first blood draw at the time of presentation to the emergency department, Laboratory Risk Indicator for NF scores, derived neutrophil-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and neutrophil-to-platelet ratio were calculated. Mann–Whitney and the area under the receiver operating characteristic curve were used for statistical analysis. Results: Our cohort included 21 patients with NF and 21 patients with OC. The Laboratory Risk Indicator for NF scores ( p value = 0.3400, AUC = 0.5862), monocyte-to-lymphocyte ratio ( p value = 0.2204, AUC = 0.6164), and platelet-to-lymphocyte ratio ( p value = 0.5489, AUC = 0.5582) were not statistically significantly different in OC and NF. Neutrophil-to-lymphocyte ratio ( p value = 0.0051, AUC = 0.7593), derived neutrophil-to-lymphocyte ratio ( p value = 0.0358, AUC = 0.69), and neutrophil-to-platelet ratio ( p value = 0.0002, AUC = 0.8254) were statistically significantly higher in NF, as compared to OC. Conclusions: This study employed the largest dataset of patients with NF and OC to compare the efficacy of different biomarkers at distinguishing between these conditions. While the Laboratory Risk Indicator for NF score failed to distinguish orbital NF from OC, other biomarkers, including the derived neutrophil-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio, and neutrophil-to-platelet ratio, accurately differentiated between these conditions. Given that these biomarkers are readily available, they could be implemented as auxiliary diagnostic tools.