ICD-10 I63.323
Billable / Specific HCC v28: 100 MCCCerebral infarction due to thrombosis of bilateral anterior cerebral arteries
About ICD-10-CM I63.323
ICD-10-CM code I63.323 represents Cerebral infarction due to thrombosis of bilateral anterior cerebral arteries. This is a billable/specific code in the Circulatory System chapter (block I63). The 2026 edition of ICD-10-CM I63.323 became effective on October 1, 2025.
Coding Tips for I63.323
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
I63.323 is a CMS-HCC v28 risk-adjustment code (category 100). 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.
I63.323 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.
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 Cerebral infarction due to thrombosis of bilateral anterior cerebral arteries. As a Major Complication/Comorbidity (MCC), this can shift the DRG assignment to a higher-weighted category, substantial reimbursement impact.
Medicare LCD Coverage for I63.323
Local Coverage Determinations (LCDs) from CMS MACs that list I63.323 as a covered diagnosis.
Showing top 10 of 351 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing I63.323.
2 Cigna
5 Medicare
CPT Codes Commonly Billed with I63.323
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.
Convert I63.323 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| I63.323 | 43401 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To I63.323
Other codes in section I60-I69 (Cerebrovascular diseases).
ICD-10 I63.323, Billing FAQ
Is ICD-10 code I63.323 billable? +
Yes, I63.323 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does I63.323 affect Medicare Advantage HCC risk adjustment? +
Yes. I63.323 maps to CMS-HCC v28 category 100. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is I63.323 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.
What ICD-9 codes does I63.323 map to? +
Per CMS GEMs, I63.323 maps to ICD-9 codes: 43401. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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