January 11, 2016
The General Equivalence Mappings (GEMs) are a series of crosswalks created by CMS to help all organizations dealing with the ICD-10 transition translate from ICD-9 to ICD-10 quickly and easily. Unfortunately, many organizations have simply installed the GEMs into their coding or billing systems without understanding the implications of doing so. This is an invitation for inaccurate coding.
The GEMs cannot be relied upon for complete and accurate coding. All coders should rely upon the ICD-10 book(s) or an officially certified electronic resource when selecting ICD-10 codes. Coders should utilize the process they were taught at the beginning of their training: seek the diagnostic terminology in the index, review the tabular for any special notes and to confirm code selection, then assign the code.
There are nearly 70,000 diagnosis codes in ICD-10. The vast majority of these (over 90%) are different in their specific language than ICD-9 codes. According to the AAPC, a recent study noted 445 instances when a single ICD-9 code can map to more than 50 possible ICD-10 codes; and 210 instances where a single ICD-9 code can map to more than 100ICD-10 codes (Healthcare Business News, Nov. 2015). It is impossible for an automated system to accurately and correctly assign ICD-10 codes.
CMS concurs with this recommendation. In their GEMs FAQ document, the organization notes that, “The GEMs are not a substitute for learning how to use ICD-10-CM and ICD-10-PCS… [I]t will be more efficient and accurate to work from the medical record documentation and then select the appropriate code(s) from the coding book or encoder system.” (See website below.)
What then is the purpose of the GEMs? CMS notes that the mappings are intended to assist with converting databases and other technical systems, including DRGs. That is, the GEMs will help us translate old material into ICD-10 for comparison purposes, but should not be used in lieu of a trained ICD-10 coder for current diagnostic reporting.
For more information on GEMs, please see the CMS FAQ : https://www.cms.gov/medicare/coding/icd10/downloads/gems-crosswalksbasicfaq.pdf
Original Posting: https://www.episource.com/blog_post/icd10coding_and_gems/