Usefulness of a risk scale based on procalcitonin for early discrimination between necrotizing fasciitis and cellulitis of the extremities

Abstract

Background and objectiveTo assess the usefulness of a risk scale based on serum procalcitonin (PCT) compared to the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scale in the early discrimination between necrotizing fasciitis (NF) and cellulitis of the extremities. Materials and methodsRetrospective study of consecutive patients with confirmed diagnosis of NF in one limb (n=11). This study group was compared with 23 consecutive patients with a diagnosis of severe limbs cellulitis during the same period. The clinical data and laboratory parameters were analyzed, the main variable was the serum level of PCT upon admission. The capacity for NF diagnosis of the two methods, PCT level and LRINEC scale score, were evaluated by ROC curve and determined by the calculation of the area under the curve (AUC). ResultsThe AUC was significantly higher with PCT measurement, both as a continuous variable and when the risk was categorized. The cut-off point for the PCT level with the highest AUC under the curve was from 0.87ng/ml (sensitivity 90.9%, specificity 82.6%), whereas it was a score of 5 on the LRINEC scale (sensitivity 72.7%, specificity 82.6%). ConclusionPCT measurement was a more effective method than the LRINEC score for early discrimination between NF and cellulitis of the extremities. A low level of PCT, associated with the patient's clinical status and physical examination is especially useful to rule out an early diagnosis of NF.