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Q21.0 — Ventricular septal defect
Q21.0
What this code means
A ventricular septal defect is a hole in the wall between the heart's two lower chambers, present from birth.
Also called: ventricular septal defect, vsd.
When this code is used
Used for ventricular septal defect.
Where it sits in ICD-10-CM
Code Q21.0 belongs to Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders, which covers codes Q00–QA1 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.
Related anatomy
Watch: related videos
Frequently asked questions
What is ICD-10-CM code Q21.0?
Q21.0 is the ICD-10-CM diagnosis code for “Ventricular septal defect”. A ventricular septal defect is a hole in the wall between the heart's two lower chambers, present from birth.
When is code Q21.0 used?
Used for ventricular septal defect. It belongs to Chapter 17 of ICD-10-CM (Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders).
This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.