Transition to the ICD-10 in the United States: An Emerging Data Chasm

In 2009, the US government mandated that all health care institutions and practitioners covered by the Health Insurance Portability and Accountability Act must transition to a new set of codes for transmitting information about patients’ conditions and treatments using the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). The transition, which was delayed twice, to these codes from the International Classification of Diseases, Ninth Revision (ICD-9) took effect in October 2015.¹ Data from health care encounters coded as ICD-10 are just now becoming available and this change to the ICD-10 has rendered ICD-coded data more challenging to interpret and use.