Coding and coverage · ICD-10-CM

Q21

Q21.2 Atrioventricular septal defect

Not billable (header)Chapter 17

Report one of the more specific codes below.

Check coverage with this diagnosis

Codes under this one

  • Q21.20 Atrioventricular septal defect, unspecified as to partial or complete
  • Q21.21 Partial atrioventricular septal defect
  • Q21.22 Transitional atrioventricular septal defect
  • Q21.23 Complete atrioventricular septal defect

Instructional notes

Chapter 17

Excludes2Not included here: the patient may have both; report both when both are present.
  • inborn errors of metabolism (E70-E88)
Notes
  • Codes from this chapter are not for use on maternal records

Q21

Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
  • acquired cardiac septal defect (I51.0)

This code

Inclusion terms
  • Atrioventricular canal defect
  • Endocardial cushion defect
  • Ostium primum atrial septal defect (type I)

Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders (Q00-QA1) · Q20-Q28 Congenital malformations of the circulatory system (Q20-Q28)

Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.

Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.