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Q21.10

Q21.10: Atrial septal defect, unspecified

Billable / specific codeICD-10-CMPOA exempt

Q21.10 is a billable, specific ICD-10-CM code for atrial septal defect, unspecified. It is valid for submission on a claim.

Check Q21.10 with the rest of the claim: free scrubber

Excludes1 inherited from the categories above Q21.10

A category’s note binds every code beneath it.

Written on Q21: Congenital malformations of cardiac septa

  • acquired cardiac septal defect (I51.0)

Excludes2 inherited from the categories above Q21.10

Not part of this code, but both may be coded when both are present.

Written on Q21.1: Atrial septal defect

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

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Medicare coverage

Q21.10 is named in 13 Medicare coverage policies: 13 listing it as supporting medical necessity. Which one applies depends on your Medicare contractor.

  • A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
  • A52868Billing and Coding: Transesophageal Echocardiography (TEE)
  • A56500Billing and Coding: Cardiac Catheterization and Coronary Angiography
  • A56505Billing and Coding: Transesophageal Echocardiography (TEE)

Alphabetic index entries that lead here

  • Defect, defective›atrial septal
  • Defect, defective›auricular septal
  • Deformity›atrial septal
  • Anomaly, anomalous›atrial›septa
  • Defect, defective›septal NOS›atrial
  • Deformity›heart›septum›auricular

Code history

Unchanged in every release from FY2024 to FY2027.

Other codes under Q21.1

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.