A General Equivalency Mapping (GEM) system is available to assist clinicians determine the correct coding options in the ICD-10 system. It’s a necessary and useful tool, but one that has distinct limitations. It provides no substitute for real training. A GEM is a general purpose tool and wasn’t originally developed for coding. It was a means of analyzing data and conducting research and studies.
GEM is a tool that can be used by clinicians to conduct searches and reverse searches to identify the correct ICD-10 codes in their practice. Translations and conversions can be done between either coding system to the other. Translating ICD-9 to ICD-10 is known as forward mapping, while ICD-10 to ICD-9 is called backward mapping. Searches will turn up approximate matches, possible combinations, and potential scenarios from which to choose and search for more data.
There are multiple versions available that have been created by vendors and professional organizations. Versions are available from the Centers for Medicare and Medicaid Services (CMS) and the National Center for Health Statistics (NCHS), along with many vendors of EMR software systems. The ease of use will be determined by multiple variables that include the developer, logic and programming used.
The results that the GEM returns are dependent upon the creating entity. Clinicians will receive entirely different coding options depending upon which GEM they’re using. The sheer volume of codes in ICD-10, combined with those that didn’t exist in the old system, means that a given GEM won’t always return the best matches or choices.
The chance of a one-to-one match is very slim, and in certain circumstances the GEM may offer none at all. All search features aren’t created equal and clinicians may find they have to try multiple search terms before the GEM returns any results at all.
It’s imperative that practitioners remember that GEMs aren’t designed to be an exact converter within a clinical setting and even an “exact match” may only be an approximation. Other coding difficulties may arise when differentiating between an initial encounter and a subsequent encounter. Some ICD-10 codes may not offer lateral solutions, which means practitioners will have to create the data themselves.
The imperfections of GEMs can have a significant impact on revenues for practices, making it imperative that clinicians bill and code at the highest possible level whenever practical and prudent. GEM results may not provide an accurate reflection of the clinician’s intent or care episodes.
Any unmapped codes that are encountered will present additional challenges for overworked practitioners struggling to adapt to a new code set and maintain revenues. Examples that reflect no translation between codes are surgical instruments, cardiovascular devices and autopsy. While the latter two are unlikely to arise in the average practice, it still points out the limitations of a typical GEM.