10ICD Code Hub

Q21.1

Header — not billable

Atrial septal defect

The ICD-10 code for atrial septal defect is Q21.1.

Q21.1 is a non-billable header code. It groups related conditions but cannot be used on its own for reimbursement — select one of the 8 more specific codes below.

Clinical notes

Excludes2 (not included here)

An Excludes2 note means the excluded condition is not part of this one, but a patient can have both at the same time — in that case both codes may be reported together.

  • ostium primum atrial septal defect (type I) (Q21.20)

Documentation support

General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.

Child codes under Q21.1

Related codes in this category

ICD-9-CM equivalent

Informational only — GEM mappings are approximate, not guaranteed one-to-one equivalents. Verify before use in billing.

View full ICD-10 → ICD-9 crosswalk →