Application of the Laboratory Risk Indicator in Necrotising Fasciitis (LRINEC) score to patients in a tropical tertiary referral centre

Abstract

The objective of this study was to assess the applicability and usefulness of the Laboratory Risk Indicator in Necrotising Fasciitis (LRINEC) score in patients from our institution. A retrospective analysis was undertaken of the case notes of all patients admitted to our facility between January 2002 and December 2005 with the admission diagnosis of necrotising fasciitis and the application of the LRINEC score upon the initial blood tests. The sensitivity, specificity and likelihood ratios were then calculated for patients with a LRINEC score of ≥6 compared with the findings of a surgical biopsy. Twenty-eight patients were identified as having the admission diagnosis of necrotising fasciitis on the hospital database and were eligible for the study. Ten of these had biopsy-proven necrotising fasciitis. With a cut-off score of ≥6, the LRINEC score had a sensitivity of 80%, specificity of 67%, a positive predictive value of 57% and a negative predictive value of 86% in distinguishing the patients with proven necrotising fasciitis from those with severe soft tissue infections. The likelihood ratio of a positive biopsy was 2.4 and the likelihood ratio of a negative biopsy was 0.3. A cut-off value of ≥6 of the LRINEC score was not overly sensitive or specific, and the likelihood ratios suggest that, at this cut-off level, the LRINEC score would have only a very small effect on the post-test probability of the patients in the studied population having necrotising fasciitis.