The purpose: (ICD-10), which was implemented for mortality coding and classification from death certificates in the U.S. It is used or medical diagnoses based on WHO's ICD-10 and the ICD-10-CM replaced ICD-9-CM.
Transitioning: ICD-9-CM was used since 1979 (which needed a change) and it was no long clinically accurate, it limited data about patients' medical conditions and hospital inpatient procedures, number of available codes limited, coding structure was restrictive.
Code set differences
ICD-9-CM codes are very different than ICD-10-CM/PCS code sets:
There are nearly 19 times as many procedure codes in ICD-10-PCS than in ICD-9-CM volume 3
There are nearly 5 times as many diagnosis codes in ICD-10-CM than in ICD-9-CM
ICD-10 has alphanumeric categories instead of numeric ones
The order of some chapters have changed, some titles have been renamed, and conditions have been grouped differently
