ICD-10-CM 2027
ICD-10 code for secondary coma
Nontraumatic coma due to underlying condition
From the official ICD-10-CM alphabetic index entry “Coma › secondary”. Page updated September 29, 2026.
About coding secondary coma
The ICD-10-CM code for secondary coma is R40.2A (Nontraumatic coma due to underlying condition).
Within R40.2 (coma), R40.2A is specifically for nontraumatic coma due to underlying condition. Related codes cover unspecified coma (R40.20), scale, eyes open (R40.21), scale, best verbal response (R40.22), scale, best motor response (R40.23) and Glasgow coma scale, total score (R40.24).
Don't report R40.2A together with the conditions in its Excludes1 note: coma scale, best motor response (R40.24.-), coma scale, best verbal response (R40.22.-), coma scale, eyes open (R40.21.-) and Glasgow coma scale, total score (R40.23.-).
Code first: underlying condition.
Don't confuse with (Excludes1 for R40.2A)
Common questions about secondary coma ICD-10 codes
What is the ICD-10 code for secondary coma?
- R40.2A — Nontraumatic coma due to underlying condition.
Is R40.2A billable?
- Yes. R40.2A is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R40.2A be used as a principal diagnosis?
- No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
Is R40.2A a CC or MCC?
- R40.2A is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.