title: A systematic review of validated methods for identifying transfusion-related ABO incompatibility reactions using administrative and claims data.
abstract: OBJECTIVE
  This paper aimed to systematically review algorithms to identify transfusion-related ABO incompatibility reactions in administrative data, with a focus on studies that have examined the validity of the algorithms.
  
  
  METHODS
  A literature search was conducted using PubMed, Iowa Drug Information Service database, and Embase. A Google Scholar search was also conducted because of the difficulty identifying relevant studies. Reviews were conducted by two investigators to identify studies using data sources from the USA or Canada because these data sources were most likely to reflect the coding practices of Mini-Sentinel data sources.
  
  
  RESULTS
  One study was found that validated International Classification of Diseases (ICD-9-CM) codes representing transfusion reactions. None of these cases were ABO incompatibility reactions. Several studies consistently used ICD-9-CM code 999.6, which represents ABO incompatibility reactions, and a technical report identified the ICD-10 code for these reactions. One study included the E-code E8760 for mismatched blood in transfusion in the algorithm. Another study reported finding no ABO incompatibility reaction codes in the Healthcare Cost and Utilization Project Nationwide Inpatient Sample database, which contains data of 2.23 million patients who received transfusions, raising questions about the sensitivity of administrative data for identifying such reactions. Two studies reported perfect specificity, with sensitivity ranging from 21% to 83%, for the code identifying allogeneic red blood cell transfusions in hospitalized patients.
  
  
  CONCLUSIONS
  There is no information to assess the validity of algorithms to identify transfusion-related ABO incompatibility reactions. Further information on the validity of algorithms to identify transfusions would also be useful.
authors.affiliation: The University of Iowa College of Public Health, Department of Epidemiology, Iowa City, IA 52242, USA. ryan-carnahan@uiowa.edu
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Carnahan
authors.forename: Vicki R
authors.initials: VR
authors.lastname: Kee
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology; D000465:Algorithms; D001787:Blood Group Incompatibility / Q000175:diagnosis / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D016208:Databases, Factual / Q000706:statistics & numerical data*; D006801:Humans; D007345:Insurance Claim Review / Q000706:statistics & numerical data; D038801:International Classification of Diseases; D012680:Sensitivity and Specificity; D065227:Transfusion Reaction; D014481:United States / Q000453:epidemiology; D054928:Validation Studies as Topic
chemical_list: D000017:ABO Blood-Group System