Q21
Congenital malformations of cardiac septa
Q21 is a non-billable ICD-10-CM code category for congenital malformations of cardiac septa. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are Q21.0 Ventricular septal defect, Q21.1 Atrial septal defect, Q21.2 Atrioventricular septal defect, Q21.3 Tetralogy of Fallot and 3 more. Its coding notes include 1 Excludes1 entry and 1 Excludes2 entry.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Chapter 17 codes can be used for life. Manifestations that are an inherent part of a specifically coded anomaly are not coded separately. A corrected malformation is reported with a personal history code.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
- acquired cardiac septal defect (I51.0)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (1 note)
- inborn errors of metabolism (E70-E88)
Notes
Also from chapter/block level (1 note)
- Codes from this chapter are not for use on maternal records
More specific codes under Q21 7
- Q21.0Ventricular septal defectBillable
- Q21.1Atrial septal defectHeader
- Q21.2Atrioventricular septal defectHeader
- Q21.3Tetralogy of FallotBillable
- Q21.4Aortopulmonary septal defectBillable
- Q21.8Other congenital malformations of cardiac septaBillable
- Q21.9Congenital malformation of cardiac septum, unspecifiedBillable