R40.2A
Billable codeNontraumatic coma due to underlying condition
The ICD-10 code for nontraumatic coma due to underlying condition is R40.2A.
Clinical notes
Code first
This code represents a manifestation of an underlying disease. Coding convention requires the underlying (etiology) code to be sequenced first, with this code listed second.
- underlying condition
Excludes1 (not coded here)
An Excludes1 note is a pure exclusion: the excluded condition and this code should never be reported together, because the two conditions cannot occur at the same time (e.g. a congenital form vs. an acquired form of the same disease).
Also known as
Alternate wording, synonyms, or specific conditions that fall under this code, listed to help confirm you've picked the right one.
- Secondary coma
Documentation support
General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.
- •Confirm the excluded condition(s) listed above are not also present — Excludes1 conditions cannot be coded together with this one.
- •This code represents a manifestation. Documentation should identify the underlying condition, which must be coded first.
- •As a general rule, code to the highest level of specificity supported by the documentation in the medical record.
Related codes in this category
Associated MS-DRGs
R40.2A can serve as the principal diagnosis for these Medicare Severity Diagnosis-Related Groups.
Informational only — actual DRG assignment also depends on procedures, complications/comorbidities (CC/MCC), discharge status, and payer-specific rules not reflected here.