ICD-10 I27.21
Billable / Specific HCC v28: 85Secondary pulmonary arterial hypertension
About ICD-10-CM I27.21
ICD-10-CM code I27.21 represents Secondary pulmonary arterial hypertension. This is a billable/specific code in the Circulatory System chapter (block I27). The 2026 edition of ICD-10-CM I27.21 became effective on October 1, 2025.
Coding Tips for I27.21
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
I27.21 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.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under I27.21. Per CMS ICD-10-CM Tabular 2026.
- (Associated) (drug-induced) (toxin-induced) pulmonary arterial hypertension NOS
- (Associated) (drug-induced) (toxin-induced) (secondary) group 1 pulmonary hypertension
Coding Notes
Code Also
- associated conditions if applicable, or adverse effects of drugs or toxins, such as:
- adverse effect of appetite depressants (T50.5X5)
- congenital heart disease (Q20-Q28)
- human immunodeficiency virus [HIV] disease (B20)
- polymyositis (M33.2-)
- portal hypertension (K76.6)
- rheumatoid arthritis (M05.-)
- schistosomiasis (B65.-)
- Sjögren syndrome (M35.0-)
- systemic sclerosis (M34.-)
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 I27.21
Local Coverage Determinations (LCDs) from CMS MACs that list I27.21 as a covered diagnosis.
Showing top 10 of 454 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing I27.21.
1 Cigna
5 Medicare
CPT Codes Commonly Billed with I27.21
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
Codes Adjacent To I27.21
Other codes in section I26-I28 (Pulmonary heart disease and diseases of pulmonary circulation).
ICD-10 I27.21, Billing FAQ
Is ICD-10 code I27.21 billable? +
Yes, I27.21 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 I27.21? +
ICD-10 I27.21 includes: (Associated) (drug-induced) (toxin-induced) pulmonary arterial hypertension NOS; (Associated) (drug-induced) (toxin-induced) (secondary) group 1 pulmonary hypertension.
Does I27.21 affect Medicare Advantage HCC risk adjustment? +
Yes. I27.21 maps to CMS-HCC v28 category 85. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with I27.21? +
Procedures frequently paired with I27.21 include: 94618, 94619, 94617.
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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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