ICD-10-CM 2027
ICD-10 code for bulbus cordis anomaly
From the official ICD-10-CM alphabetic index entry “Anomaly, anomalous (congenital) (unspecified type) › bulbus cordis”. Page updated September 29, 2026.
About coding bulbus cordis anomaly
The ICD-10-CM code for bulbus cordis anomaly is Q21.9 (Congenital malformation of cardiac septum, unspecified).
Within Q21, choose Q21.9 (Congenital malformation of cardiac septum, unspecified) only when documentation doesn't support a more specific option: ventricular septal defect (Q21.0), atrial septal defect (Q21.1), atrioventricular septal defect (Q21.2), tetralogy of Fallot (Q21.3), Aortopulmonary septal defect (Q21.4) and other congenital malformations of cardiac septa (Q21.8).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 306 (Cardiac Congenital and Valvular Disorders with MCC, relative weight 1.546) and DRG 307 (Cardiac Congenital and Valvular Disorders without MCC, relative weight 0.9148), in MDC 05 (Diseases and Disorders of the Circulatory System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about bulbus cordis anomaly ICD-10 codes
What is the ICD-10 code for bulbus cordis anomaly?
- Q21.9 — Congenital malformation of cardiac septum, unspecified.
Is Q21.9 billable?
- Yes. Q21.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q21.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q21.9 as a principal diagnosis.
Is Q21.9 a CC or MCC?
- No. Q21.9 is neither a CC nor an MCC under MS-DRG v44.0.