ICD-10 I28.9
Billable / Specific HCC v28: 85Disease of pulmonary vessels, unspecified
About ICD-10-CM I28.9
ICD-10-CM code I28.9 represents Disease of pulmonary vessels, unspecified. This is a billable/specific code in the Circulatory System chapter (block I28). The 2026 edition of ICD-10-CM I28.9 became effective on October 1, 2025.
Coding Tips for I28.9
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
I28.9 is a CMS-HCC v28 risk-adjustment code (category 85). 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.
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.
Medicare LCD Coverage for I28.9
Local Coverage Determinations (LCDs) from CMS MACs that list I28.9 as a covered diagnosis.
Showing top 10 of 140 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing I28.9.
2 Cigna
4 Medicare
CPT Codes Commonly Billed with I28.9
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 I28.9 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 |
|---|---|---|
| I28.9 | 4179 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To I28.9
Other codes in section I26-I28 (Pulmonary heart disease and diseases of pulmonary circulation).
ICD-10 I28.9, Billing FAQ
Is ICD-10 code I28.9 billable? +
Yes, I28.9 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does I28.9 affect Medicare Advantage HCC risk adjustment? +
Yes. I28.9 maps to CMS-HCC v28 category 85. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What ICD-9 codes does I28.9 map to? +
Per CMS GEMs, I28.9 maps to ICD-9 codes: 4179. 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 June 2, 2026.
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