ICD-10-CM 2027
ICD-10 code for Eisenmenger's defect
From the official ICD-10-CM alphabetic index entry “Defect, defective › Eisenmenger's”. Page updated September 29, 2026.
About coding Eisenmenger's defect
The ICD-10-CM code for Eisenmenger's defect is Q21.8 (Other congenital malformations of cardiac septa).
Within Q21, choose Q21.8 (Other congenital malformations of cardiac septa) 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 congenital malformation of cardiac septum, unspecified (Q21.9).
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 Eisenmenger's defect ICD-10 codes
What is the ICD-10 code for Eisenmenger's defect?
- Q21.8 — Other congenital malformations of cardiac septa.
Is Q21.8 billable?
- Yes. Q21.8 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q21.8 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q21.8 as a principal diagnosis.
Is Q21.8 a CC or MCC?
- No. Q21.8 is neither a CC nor an MCC under MS-DRG v44.0.