GEMs is a term you will be very familiar with once you start your ICD-10 transition.
General Equivalence Mappings (GEMs) for the ICD-10-CM diagnostic codes were created in a joint effort by CMS and The Centers for Disease Control and Prevention (CDC). GEMs can help you to map codes forward, from ICD-9-CM to ICD-10-CM, and backwards, from ICD-10-CM to ICD-9-CM.
GEMs are only a helpful starting point in finding an equivalent code. Quite often, there is not a one-to-one match between codes and unfortunately many of those matches are only mapped to an unspecific code.
To learn more about how to find the correct code when there is not a one-to-one match see Find-A-Codes Map-A-Code tool. Map-A-Code uses the Medicare General Equivalence Mappings (GEMs) and Reimbursement Mappings (RMs) to map codes from ICD-9-CM (v1 and v3) to ICD-10-CM and ICD-10-PCS.
NOTE:This information and much more can also be found at InstaCode Institute. With over 20 specialty books to help you transition to ICD-10. Books will be available January 2015. Don’t delay; visit InstaCode.com to pre-order your specialty books.