ICD-10 R40.2A
Billable / Specific HCC v28: 80 MCCNontraumatic coma due to underlying condition
About ICD-10-CM R40.2A
ICD-10-CM code R40.2A represents Nontraumatic coma due to underlying condition. This is a billable/specific code in the Symptoms, Signs, and Abnormal Findings chapter (block R40). The 2026 edition of ICD-10-CM R40.2A became effective on October 1, 2025.
Coding Tips for R40.2A
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
R40.2A is a CMS-HCC v28 risk-adjustment code (category 80). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
R40.2A is designated MCC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-MCC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag MCC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under R40.2A. Per CMS ICD-10-CM Tabular 2026.
- Secondary coma
Type 1 Excludes
Pure excludes, these codes can never be coded together with R40.2A. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- coma scale, best motor response (R40.24.-)
- coma scale, best verbal response (R40.22.-)
- coma scale, eyes open (R40.21.-)
- Glasgow coma scale, total score (R40.23.-)
Coding Notes
Code First
- underlying condition
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, MCC
codes Nontraumatic coma due to underlying condition. As a Major Complication/Comorbidity (MCC), this can shift the DRG assignment to a higher-weighted category, substantial reimbursement impact.
Medicare LCD Coverage for R40.2A
Local Coverage Determinations (LCDs) from CMS MACs that list R40.2A as a covered diagnosis.
Showing top 10 of 218 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing R40.2A.
5 Medicare
CPT Codes Commonly Billed with R40.2A
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To R40.2A
Other codes in section R40-R46 (Symptoms and signs involving cognition, perception, emotional state and behavior).
ICD-10 R40.2A, Billing FAQ
Is ICD-10 code R40.2A billable? +
Yes, R40.2A is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to R40.2A? +
ICD-10 R40.2A includes: Secondary coma.
What codes are Type 1 Excludes for R40.2A? +
Type 1 Excludes (never code together with R40.2A): coma scale, best motor response (R40.24.-); coma scale, best verbal response (R40.22.-); coma scale, eyes open (R40.21.-)
Does R40.2A affect Medicare Advantage HCC risk adjustment? +
Yes. R40.2A maps to CMS-HCC v28 category 80. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is R40.2A a CC or MCC for inpatient DRG? +
Yes, this code is designated as MCC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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