A Resident-to-Resident Discussion About ICD-10

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September 2015
As the ICD-10 transition is upon us, I sat down to discuss the transition to ICD-10 with Margaret Fleming, MD, of Emory University. Dr. Fleming and her colleagues recently published a manuscript on this topic, entitled “Magnitude of Impact, Overall and on Subspecialties, of Transitioning in Radiology from ICD-9 to ICD-10 Codes” in the JACR™. As Dr. Fleming explains, the International Classification of Diseases (ICD) diagnosis coding system is designed to track epidemiologic data worldwide, but it is also integral to medical billing and reimbursement. The combination of the CPT and ICD codes is used to determine medical necessity, which is a criterion for reimbursement.


The ICD system will transition from ICD-9 to ICD-10 on October 1, 2015. The transition to ICD-10 will dramatically increase the number of codes. ICD-9 contained 14,025 codes, while ICD-10 jumps to 69,823 codes. Dr. Fleming’s paper examined the impact of the conversion on radiology practices.

Fleming and her co-authors summarize the article as follows:

• Of 14,025 ICD-9 codes overall, only 3,407 were used as the primary diagnosis in any of more than one-half million claims in a large health care system and of those, just 348 applied to 90 percent of all claims.

• The 348 primary ICD-9 codes for 90 percent of all health system radiology claims map to 2,048 ICD-10 claims, indicating that overall, radiology practices should anticipate a 5.9-fold increase in new codes as part of their ICD-10 conversion.

• Code conversion impact factors vary greatly by subspecialty with breast imaging predicted to experience the least impact (a 1.1-fold code increase); musculoskeletal imaging is predicted to be affected most (28.8).

• As radiology practices transition to ICD-10, empiric data should be used to guide and prioritize educational and operational initiatives.


While ICD-10 heightens the complexity of the coding system, the impact will be minimized if radiologists continue to dictate quality reports. Remember to include the what, when, and where in every report so billers and coders will have the necessary clinical information to assign the appropriate ICD-10 code.

By Colin Segovis, MD, PhD (@colinsegovis), RFS secretary and resident at Wake Forest University

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