title: Efficiency of International Classification of Diseases, Ninth Revision, billing code searches to identify emergency department visits for blood or body fluid exposures through a statewide multicenter database.
abstract: BACKGROUND
  Blood and body fluid exposures are frequently evaluated in emergency departments (EDs). However, efficient and effective methods for estimating their incidence are not yet established.
  
  
  OBJECTIVE
  Evaluate the efficiency and accuracy of estimating statewide ED visits for blood or body fluid exposures using International Classification of Diseases, Ninth Revision (ICD-9), code searches.
  
  
  METHODS
  Secondary analysis of a database of ED visits for blood or body fluid exposure.
  
  
  METHODS
  EDs of 11 civilian hospitals throughout Rhode Island from January 1, 1995, through June 30, 2001.
  
  
  METHODS
  Patients presenting to the ED for possible blood or body fluid exposure were included, as determined by prespecified ICD-9 codes.
  
  
  METHODS
  Positive predictive values (PPVs) were estimated to determine the ability of 10 ICD-9 codes to distinguish ED visits for blood or body fluid exposure from ED visits that were not for blood or body fluid exposure. Recursive partitioning was used to identify an optimal subset of ICD-9 codes for this purpose. Random-effects logistic regression modeling was used to examine variations in ICD-9 coding practices and styles across hospitals. Cluster analysis was used to assess whether the choice of ICD-9 codes was similar across hospitals.
  
  
  RESULTS
  The PPV for the original 10 ICD-9 codes was 74.4% (95% confidence interval [CI], 73.2%-75.7%), whereas the recursive partitioning analysis identified a subset of 5 ICD-9 codes with a PPV of 89.9% (95% CI, 88.9%-90.8%) and a misclassification rate of 10.1%. The ability, efficiency, and use of the ICD-9 codes to distinguish types of ED visits varied across hospitals.
  
  
  CONCLUSIONS
  Although an accurate subset of ICD-9 codes could be identified, variations across hospitals related to hospital coding style, efficiency, and accuracy greatly affected estimates of the number of ED visits for blood or body fluid exposure.
authors.affiliation: Department of Community Health, Alpert Medical School of Brown University, Providence, Rhode Island, USA.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Rosen
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Roland C
authors.initials: RC
authors.lastname: Merchant
mesh_terms: D017848:Blood-Borne Pathogens; D001826:Body Fluids; D016000:Cluster Analysis; D016208:Databases, Factual; D004526:Efficiency; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D004781:Environmental Exposure / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases; D016015:Logistic Models; D011237:Predictive Value of Tests; D012237:Rhode Island