Coding and coverage · ICD-10-CM
Instructional notes
Chapter 17
Excludes2Not included here: the patient may have both; report both when both are present.
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)
Q21.2
Inclusion terms
- Atrioventricular canal defect
- Endocardial cushion defect
- Ostium primum atrial septal defect (type I)
This code
Inclusion terms
- Intermediate atrioventricular canal
- Intermediate atrioventricular septal defect
- Intermediate endocardial cushion defect
- Ostium primum atrial septal defect (type I) with separate atrioventricular valves and a small or restrictive inlet VSD
- Transitional atrioventricular canal
- Transitional endocardial cushion defect
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.