ICD-10 CM to ICD-9 CM Diagnosis Code GEM

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This dataset shows the ICD-10 (International Classification of Diseases), CM (Clinical Modification), 10th Edition (2016 to 2018) to ICD-9 CM Diagnosis Codes (GEM) General Reimbursement Mappings. These ICD-10-CM codes are to be used for services provided from October 1, 2016 through September 30, 2018.


The purpose of the GEMs is to create a useful, practical, code to code translation reference dictionary for both code sets, and to offer acceptable translation alternatives wherever possible.

The I-10 and I-9 GEMs are used to facilitate links between the diagnosis codes in I-9 volume 3 and the new I-10 code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs. This is covered in more detail in section 2.

The I-10 to I-9 GEM contains an entry for every I-10 code. Not all I-9 codes are contained in the I-10 to I-9 GEM; the I-10 to I-9 GEM contains only those I-9 codes which are plausible translations of the I-10 codes. The translations given are based on the I-10 code looked up, the source system code in the I-10 to I-9 GEM.

The I-10 to I-9 GEM can be used to convert I-9 based systems or applications to I-10 based applications, or create one-to-one backward mappings (also known as a crosswalk) from incoming I-10 based records to I-9 based legacy systems. This is accomplished by using the I-10 to I-9 GEM, but looking up the target system code (I-9) to see all the source system possibilities (I-10). This is called reverse lookup.

Date Created


Last Modified




Update Frequency


Temporal Coverage

2016-10-01 to 2018-09-30

Spatial Coverage

United States


John Snow Labs => Centers for Medicare and Medicaid Services

Source License URL

John Snow Labs Standard License

Source License Requirements


Source Citation



Clinical Software, CCS, Clinical Classifications Software, Clinical Classifications Software for Services and Procedures, Code Book, ICD-10-CM Definition, ICD-10-CM Book, ICD-10-CM Manual, ICD-10-CM and ICD-10-PCS Coding Handbook, ICD 10 Codes List, ICD 10 Procedure Code, ICD 10 Codes, ICD Codes

Other Titles

ICD-10-CM to ICD-9-CM Diagnosis Codes General Reimbursement Mappings Clinical Software, ICD-10-CM to ICD-9-CM Diagnosis Codes General Reimbursement Mappings CCS, ICD-10-CM to ICD-9-CM Diagnosis Codes General Reimbursement Mappings Clinical Classifications Software

Name Description Type Constraints
YearYear or version of ICD-10 code when it was published.date-
ICD10CM_CodeICD-10 code (3 to 7 characters) left justified in an 8-character field that uniquely identifies an illness.string-
ICD9CM_CodeInternational Classification of Diseases 9th Revision Clinical Modification (I-9) left justified in a 14-character field that uniquely identifies an illness.string-