Validation of Laboratory Risk Indicator for Necrotizing Fasciitis (<scp>LRINEC</scp>) score and establishment of novel score in Japanese patients with necrotizing fasciitis (J‐<scp>LRINEC</scp> score)

The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score is widely used to distinguish between necrotizing fasciitis and cellulitis. However, LRINEC scores are not as sensitive or specific as initially reported, possibly due to differences in patient backgrounds in different countries. Here, we examined the validity of LRINEC scores in Japanese patients. We also investigated the possibility of developing a new scoring system. Patients with necrotizing fasciitis (n = 56) and cellulitis (n = 209) were retrospectively evaluated. The data were split into training (n = 199) and validation (n = 66) datasets. A logistic regression analysis was used to calculate the C-statistics of the LRINEC scores. A new equation was formulated using logistic regression analysis with an appropriate variable selection (Laboratory Risk Indicator for Necrotizing Fasciitis for Japanese Patients [J-LRINEC] score). The J-LRINEC score had a C-statistic of 0.9683, sensitivity of 91.4%, and specificity of 84.8%. The LRINEC score had a C-statistic of 0.914 and specificity of 96%; however, its usefulness was limited by its sensitivity of 68.9%. Our results suggest that the LRINEC score is valid for Japanese patients; however, the J-LRINEC score showed higher sensitivity and specificity, suggesting that it may be a useful tool for differentiating cellulitis from necrotizing fasciitis among Japanese patients.