Q21: Congenital malformations of cardiac septa
Codes under Q21 (Congenital malformations of cardiac septa). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| Q21.0 | Ventricular septal defect | ✓ |
| Q21.0 | Ventricular septal defect | ✓ |
| Q21.1 | Atrial septal defect | — |
| Q21.1 | Atrial septal defect | — |
| Q21.2 | Atrioventricular septal defect | — |
| Q21.2 | Atrioventricular septal defect | — |
| Q21.3 | Tetralogy of Fallot | ✓ |
| Q21.3 | Tetralogy of Fallot | ✓ |
| Q21.4 | Aortopulmonary septal defect | ✓ |
| Q21.4 | Aortopulmonary septal defect | ✓ |
| Q21.8 | Other congenital malformations of cardiac septa | ✓ |
| Q21.8 | Other congenital malformations of cardiac septa | ✓ |
| Q21.9 | Congenital malformation of cardiac septum, unspecified | ✓ |
| Q21.9 | Congenital malformation of cardiac septum, unspecified | ✓ |
| Q21.10 | Atrial septal defect, unspecified | ✓ |
| Q21.10 | Atrial septal defect, unspecified | ✓ |
| Q21.11 | Secundum atrial septal defect | ✓ |
| Q21.11 | Secundum atrial septal defect | ✓ |
| Q21.12 | Patent foramen ovale | ✓ |
| Q21.12 | Patent foramen ovale | ✓ |
| Q21.13 | Coronary sinus atrial septal defect | ✓ |
| Q21.13 | Coronary sinus atrial septal defect | ✓ |
| Q21.14 | Superior sinus venosus atrial septal defect | ✓ |
| Q21.14 | Superior sinus venosus atrial septal defect | ✓ |
| Q21.15 | Inferior sinus venosus atrial septal defect | ✓ |
| Q21.15 | Inferior sinus venosus atrial septal defect | ✓ |
| Q21.16 | Sinus venosus atrial septal defect, unspecified | ✓ |
| Q21.16 | Sinus venosus atrial septal defect, unspecified | ✓ |
| Q21.19 | Other specified atrial septal defect | ✓ |
| Q21.19 | Other specified atrial septal defect | ✓ |
| Q21.20 | Atrioventricular septal defect, unspecified as to partial or complete | ✓ |
| Q21.20 | Atrioventricular septal defect, unspecified as to partial or complete | ✓ |
| Q21.21 | Partial atrioventricular septal defect | ✓ |
| Q21.21 | Partial atrioventricular septal defect | ✓ |
| Q21.22 | Transitional atrioventricular septal defect | ✓ |
| Q21.22 | Transitional atrioventricular septal defect | ✓ |
| Q21.23 | Complete atrioventricular septal defect | ✓ |
| Q21.23 | Complete atrioventricular septal defect | ✓ |
Frequently asked questions
What is ICD-10-CM code Q21?
Q21 is an ICD-10-CM category covering Congenital malformations of cardiac septa. It contains 38 more specific diagnosis codes, 34 of which are billable.
Is Q21 a billable code?
No — Q21 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example Q21.0 — Ventricular septal defect). 34 of the 38 codes under Q21 are billable.
What codes fall under Q21?
Q21 includes Q21.0, Q21.0, Q21.1, Q21.1, Q21.2, plus 33 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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