Time Is Fascia: Laboratory and Anamnestic Risk Indicators for Necrotizing Fasciitis.

Background: Necrotizing fasciitis is a potentially fatal soft tissue infection in which the timing of surgical intervention significantly affects clinical outcome. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score, the Site other than the lower limb, Immunosuppression, Age <60 years, Renal impairment (creatinine >141), and Inflammatory markers (CRP ≥150, WCC >25) (SIARI) score, and procalcitonin levels are intended to aid in the decision-making process to differentiate between necrotizing fasciitis and soft tissue infections. Methods: A retrospective analysis of cases of necrotizing fasciitis and soft tissue infections treated at Klinikum Nürnberg was performed. The two scores as well as procalcitonin levels were tested for their diagnostic value and a new score, the Laboratory and Anamnestic Risk Indicator for Necrotizing Fasciitis (LARINF), was created based on the results. Results: Procalcitonin, LRINEC score, and SIARI score showed insufficient discriminatory ability in our study. The newly created LARINF score combined laboratory parameters of the LRINEC score (hemoglobin and C-reactive protein) with procalcitonin and three comorbidities, resulting in a sensitivity of 84% and a specificity of 75% and the highest area under the receiver operating characteristic (ROC) curve of 0.83. Conclusions: The LARINF score is a novel decision-supporting tool. The decision, in which cases surgical exploration should be initiated, remains a clinical one. However, the score seems to provide an improved basis for identifying a rare clinical picture.