Non-Billable / Non-Specific Code
ICD-10-CM Q21 is the diagnosis code for Congenital malformations of cardiac septa. This code falls under the section "Congenital malformations of the circulatory system" within Chapter 17 — Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as Q21. They are mutually exclusive:
Understanding where Q21 sits in the ICD-10-CM classification helps ensure proper coding:
No, Q21 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
Q21 is the ICD-10-CM diagnosis code for "Congenital malformations of cardiac septa". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
Q21 is located in Section Q20-Q28 — "Congenital malformations of the circulatory system" within Chapter 17 of the ICD-10-CM Tabular List.
Q21 has 7 sub-code(s) that provide more specific detail: Q21.0, Q21.1, Q21.2, Q21.3, Q21.4 and more.
Use Q21 when the patients documented diagnosis matches "Congenital malformations of cardiac septa" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Congenital malformations of cardiac septa is Q21.
No, Q21 is non-billable. Use a more specific sub-code for primary diagnosis billing.
Q21 is in Chapter 17 of the ICD-10-CM Tabular List.
Type 1 Excludes for Q21 include: acquired cardiac septal defect (I51.0).
Yes, Q21 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.