ICD-10 Q21.9
Billable / SpecificCongenital malformation of cardiac septum, unspecified
About ICD-10-CM Q21.9
ICD-10-CM code Q21.9 represents Congenital malformation of cardiac septum, unspecified. This is a billable/specific code in the Congenital Malformations chapter (block Q21). The 2026 edition of ICD-10-CM Q21.9 became effective on October 1, 2025.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under Q21.9. Per CMS ICD-10-CM Tabular 2026.
- Septal (heart) defect NOS
Medicare LCD Coverage for Q21.9
Local Coverage Determinations (LCDs) from CMS MACs that list Q21.9 as a covered diagnosis.
Showing top 10 of 228 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing Q21.9.
1 Aetna
2 Cigna
5 Medicare
CPT Codes Commonly Billed with Q21.9
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 Q21.9 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 |
|---|---|---|
| Q21.9 | 7459 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To Q21.9
Other codes in section Q20-Q28 (Congenital malformations of the circulatory system).
ICD-10 Q21.9, Billing FAQ
Is ICD-10 code Q21.9 billable? +
Yes, Q21.9 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 Q21.9? +
ICD-10 Q21.9 includes: Septal (heart) defect NOS.
What ICD-9 codes does Q21.9 map to? +
Per CMS GEMs, Q21.9 maps to ICD-9 codes: 7459. 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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