Q21.4 – Aortopulmonary septal defect
ICD-10-CM 2027 diagnosis code · Congenital malformations of the circulatory system
ICD-10-CM code
Q21.4
- Code
Q21.4(claims format:Q214)- Description
- Aortopulmonary septal defect
- Billable
- Yes – valid for HIPAA-covered transactions
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 17. Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1)
- Block
- Q20-Q28 Congenital malformations of the circulatory system
- Parent codes
- Q21
Notes for Q21.4
Applicable to:
- Aortic septal defect
- Aortopulmonary window
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
Q21 – Congenital malformations of cardiac septa
Excludes1 (not coded here):
- acquired cardiac septal defect (I51.0)
Index terms for Q21.4
Entries in the ICD-10-CM alphabetic index that lead to this code:
- Window, aorticopulmonary
- Defect, defective, aorticopulmonary septum
- Fenestration, fenestrated, aortico-pulmonary
- Imperfect, closure, septum, aorticopulmonary
- Absence, septum, between aorta and pulmonary artery
- Agenesis, septum, between aorta and pulmonary artery
- Communication, between, base of aorta and pulmonary artery
- Imperfect, closure, septum, between aorta and pulmonary artery
Related codes in Q21
Frequently asked questions
What is ICD-10 code Q21.4?
Q21.4 is the ICD-10-CM code for aortopulmonary septal defect, in the block Q20-Q28 (Congenital malformations of the circulatory system).
Is Q21.4 a billable code?
Yes. Q21.4 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.
What category does Q21.4 belong to?
It belongs to category Q21 – Congenital malformations of cardiac septa.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.