Question:
Is there a one-to-one match between ICD-9-CM and ICD-10?
Answer:
According to the Centers for Medicare & Medicaid Services (CMS), there is not a one-to-one match between ICD-9-CM and ICD-10, and there are several reasons for that, including the following.
- There are new concepts in ICD-10 that are not present in ICD-9-CM.
- For a small number of codes, there is no matching code in the general equivalence mappings (GEMs).
- There may be multiple ICD-9-CM codes for a single ICD-10 code.
- There may be multiple ICD-10 codes for a single ICD-9-CM code.