Q21.1 vs Q21.20
Q21.1 (Atrial septal defect) compared with Q21.20 (Atrioventricular septal defect, unspecified as to partial or complete), from the official CMS tabular data. Both may be reported when both conditions are documented (Excludes2).
Can these codes be reported together?
Yes, when both are documented. Q21.1 carries an Excludes2 note covering Q21.20: “ostium primum atrial septal defect (type I) (Q21.20)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
Side by side
| Q21.1Atrial septal defect | Q21.20Atrioventricular septal defect, unspecified as to partial or complete | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | Q00-Q99 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99) | Q00-Q99 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-Q99) |
| Definition | Atrial septal defect is a non-billable ICD-10-CM category code (Q21.1). | Atrioventricular septal defect, unspecified as to partial or complete is a billable ICD-10-CM diagnosis code (Q21.20). |
| Includes | — | Atrioventricular canal, NOS Endocardial cushion defect NOS Ostium primum atrial septal defect (type I) NOS |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources