title: Magnitude of Impact, Overall and on Subspecialties, of Transitioning in Radiology from ICD-9 to ICD-10 Codes.
abstract: OBJECTIVE
  Converting the nation's International Classification of Diseases (ICD) diagnosis coding system, from 14,025 ICD-9 to 69,823 ICD-10 codes, is projected to have enormous financial and operational implications. We aimed to assess the magnitude of impact that this code conversion will have on radiology claims.
  
  
  METHODS
  The most frequently billed ICD-9 diagnosis codes for 588,523 radiology claims from five hospitals and affiliated outpatient sites during a 12-month period were mapped to matching ICD-10 codes using a Medicare-endorsed tool. The code-conversion impact factor was calculated for the entire radiology system, and each individual subspecialty division.
  
  
  RESULTS
  Of all ICD-9 codes, only 3,407 (24.3%) were used to report any primary diagnosis. Of all claims, 50% were billed using just 37 (0.3%) primary codes; 75% with 131 (0.5%), and 90% with 348 (2.5%). Those 348 ICD-9 codes mapped onto 2,048 ICD-10 codes (5.9-fold impact), representing just 2.9% of all ICD-10 codes. By subspecialty, the conversion impact factor varied greatly, from 1.1 for breast (11 ICD-9 to 12 ICD-10 codes) to 28.8 for musculoskeletal imaging (146 to 4,199). The community division, reflecting a general practice mix, saw a conversion impact factor of 5.8 (254 to 1,471).
  
  
  CONCLUSIONS
  Fewer than 3% of all ICD-9 and ICD-10 codes are used to report an overwhelming majority of all radiology claims. Although the number of commonly used codes will expand 5.9-fold overall, musculoskeletal imaging will experience a projected 28.8-fold explosion. Radiology practices should target their ICD educational and operational conversion efforts in an evidence-based manner.
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia. Electronic address: margaret.fleming@emory.edu.
authors.forename: Margaret
authors.initials: M
authors.lastname: Fleming
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Dan
authors.initials: D
authors.lastname: MacFarlane
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: William E
authors.initials: WE
authors.lastname: Torres
authors.affiliation: Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Richard
authors.initials: R
authors.lastname: Duszak
mesh_terms: D016208:Databases, Factual; D004282:Documentation / Q000145:classification; D004502:Education, Medical, Continuing; D006801:Humans; D007344:Insurance Claim Reporting / Q000145:classification* / Q000191:economics; D007349:Insurance, Health, Reimbursement / Q000191:economics / Q000706:statistics & numerical data; D038801:International Classification of Diseases / Q000592:standards*; D006278:Medicare; D010360:Patient Transfer; D011871:Radiology / Q000145:classification*; D014481:United States
keywords: Coding billing; ICD-10; ICD-9; documentation; reimbursement