Q21 ICD-10-CM Code: Congenital malformations of cardiac septa
A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.
Official description
Q21Congenital malformations of cardiac septa
ICD-10-CM diagnosis code · United States clinical modification
Where Q21 sits
- 1
Chapter 17
Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1)
- 2
Section
Congenital malformations of the circulatory system (Q20-Q28)
- 3
Category Q21
Congenital malformations of cardiac septa
- 4
Code Q21
Congenital malformations of cardiac septa
Codes under Q21
Q21 is a non-billable category. Choose the child code that best matches the documented diagnosis.
Notes for this code
Inclusion terms
No inclusion terms are listed for Q21.
Code first
No “code first” instruction is listed for Q21.
Use additional code
No “use additional code” instruction is listed for Q21.
Excludes1
Conditions that should not be reported together with this code.
- acquired cardiac septal defect (I51.0)
Excludes2
Conditions not included here that may be reported separately when present.
No Excludes2 note is listed for Q21.
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.
Frequently asked questions
What does ICD-10-CM code Q21 mean?
Q21 is the FY 2027 U.S. ICD-10-CM code for “Congenital malformations of cardiac septa.”
Is Q21 a billable or specific ICD-10-CM code?
No. Q21 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.
Where is Q21 located in ICD-10-CM?
Q21 is listed in Chapter 17, Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1), within Congenital malformations of the circulatory system (Q20-Q28) (Q20–Q28), under category Q21, Congenital malformations of cardiac septa.
What coding notes are listed for Q21?
No inclusion terms are listed for Q21 in this reference record. No code-first instruction is listed. Excludes1 notes: acquired cardiac septal defect (I51.0). No Excludes2 note is listed.