title: Inadequate Sensitivity of Laboratory Risk Indicator to Rule Out Necrotizing Fasciitis in the Emergency Department.
abstract: BACKGROUND
  Necrotizing fasciitis (NF) is a life-threatening illness, particularly when surgical debridement is delayed. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score was developed to identify patients at higher risk for NF. Despite limited information in this regard, the LRINEC score is often used to "rule out" NF if negative. We describe the sensitivity of the LRINEC score in emergency department (ED) patients for the diagnosis of NF.
  
  
  METHODS
  We conducted a chart review of ED patients in whom coding of hospital discharge diagnoses included NF. We employed standard methods to minimize bias. We used laboratory data to calculate the LRINEC score, and confirmed the diagnosis of NF via explicit chart review. We then calculated the sensitivity of a positive LRINEC score (standardly defined as six or greater) in our cohort. We examined the role of patient characteristics in the performance of the LRINEC score. Finally, we performed sensitivity analyses to estimate whether missing data for c-reactive protein (CRP) results were likely to impact our results.
  
  
  RESULTS
  Of 266 ED patients coded as having a discharge diagnosis of NF, we were able to confirm the diagnosis, by chart review, in 167. We were able to calculate a LRINEC score in only 80 patients (due to absence of an initial CRP value); an LRINEC score of 6 or greater had a sensitivity of 77%. Sensitivity analyses of missing data supported our finding of inadequate sensitivity to rule out NF. In sub-analysis, NF patients with concurrent diabetes were more likely to be accurately categorized by the LRINEC score.
  
  
  CONCLUSIONS
  Used in isolation, the LRINEC score is not sufficiently sensitive to rule out NF in a general ED population.
authors.affiliation: Keck School of Medicine of the University of Southern California, Department of Emergency Medicine, Los Angeles, California.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Burner
authors.affiliation: Keck School of Medicine of the University of Southern California, Department of Emergency Medicine, Los Angeles, California.
authors.forename: Sean O
authors.initials: SO
authors.lastname: Henderson
authors.affiliation: George Washington University, Department of Emergency Medicine, Washington, DC.
authors.forename: Guenevere
authors.initials: G
authors.lastname: Burke
authors.affiliation: Keck School of Medicine of the University of Southern California, Department of Emergency Medicine, Los Angeles, California.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Nakashioya
authors.affiliation: University of California Los Angeles, Department of Emergency Medicine, Los Angeles, California.
authors.forename: Jerome R
authors.initials: JR
authors.lastname: Hoffman
mesh_terms: D003646:Debridement / Q000379:methods*; D003661:Decision Support Techniques; D057210:Delayed Diagnosis; D004636:Emergency Service, Hospital; D019115:Fasciitis, Necrotizing / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012017:Referral and Consultation; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012867:Skin / Q000382:microbiology / Q000473:pathology*; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000473:pathology; D014481:United States / Q000453:epidemiology