In probably the most important change to the FY2021 ICD-10-CM guidelines, the reporting of Glasgow Coma Scale codes has been revised to refer only to trauma cases.

• In FY 2020, Official Coding Guidelines Section I.C.18.e read: “The coma scale codes (R40.2-) can be used in conjunction with traumatic brain injury codes, acute cerebrovascular disease or sequelae of cerebrovascular disease codes. These codes are primarily for use by trauma registries, …. The coma scale may also be used to assess the status of the central nervous system for other non-trauma conditions, …”
• For FY 2021, I.C.18.e was revised to read: “The coma scale codes (R40.2-) can be used in conjunction with traumatic brain injury codes. These codes are primarily for use by trauma registries, but they may be used in any setting where this information is collected."

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During her annual ICD-10 update webinar, Nelly Leon-Chisen, Director of Coding and Classification at the American Hospital Association and its representative to the ICD-10 Coordination and Maintenance Committee, confirmed the intent of the guideline to prohibit Glasgow Coma Scale reporting in non-trauma. In response to an inquiry, Ms. Leon-Chisen replied:

“For the coma scale guideline, the codes can now only be used for traumatic brain injury. The rationale is that as the codes were expanded to more and more conditions, there were more questions coming in which required review by the Editorial Advisory Board. It became clear that people were looking to use them for situations the codes were never intended for and therefore couldn’t be applied. After considerable discussion, the EAB recommended that the application of those codes be rolled back to their original intent, which was for traumatic brain injuries.”

Ms. Leon-Chisen also stated that Coding Clinic does not plan to publish a further clarification. Given the confusion and questions about the change we hope they will reconsider and offer additional specific guidance.

Glasgow Coma Scale is the only objective standard for quantitating the degree of altered level of consciousness, diagnosing coma, and are used almost uniformly in the medical community in all conditions (traumatic and non-traumatic). Glasgow Coma Scale scores that generally correspond to clinical levels of altered consciousness are shown below:

• 3–8 points = Severe: Coma
• 9–12 points = Moderate: Stupor/obtundation
• 13–15 points = Minor: Lethargy

Coma may also be diagnosed by the clinician’s overall subjective impression of a patient’s level of consciousness and responsiveness.

• Coma codes, including the unspecified coma code, are MCCs
• Obtundation is not indexed (i.e., no code)
• Stupor (R40.1), somnolence/drowsiness (R40.0) and lethargy (R53.83) are non-CCs

While the Glasgow Coma Scale can no longer be reported in non-trauma cases, coma can be and is an MCC. We recommend coding and CDI specialists consider a query for coma when the record reports a Glasgow Coma Scale score of </= to 8.