Q23.4 Hypoplastic left heart syndrome
The ICD-10-CM code for Hypoplastic left heart syndrome is Q23.4 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- Q20-Q28: Congenital malformations of the circulatory system (Q20-Q28)
- Category Q23
- 11 codes (9 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to Q23.4:
- Syndrome › hypoplastic left-heart
- Hypoplasia, hypoplastic › left heart syndrome
- Hypoplasia, hypoplastic › aorta, aortic › ascending, in hypoplastic left heart syndrome
- Atresia, atretic › mitral valve › in hypoplastic left heart syndrome
- Atresia, atretic › aortic (orifice) (valve) › congenital with hypoplasia of ascending aorta and defective development of left ventricle (with mitral stenosis)
- Atresia, atretic › aortic (orifice) (valve) › in hypoplastic left heart syndrome
- Development › defective, congenital › left ventricle › in hypoplastic left heart syndrome
- Hypoplasia, hypoplastic › aorta, aortic › valve › in hypoplastic left heart syndrome
U.S. Hospital Utilization
- An estimated 6,040 U.S. inpatient stays in 2023 included Q23.4 among the documented diagnoses.
- 1,725 stays listed it as the principal diagnosis.
Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.
Official Coding Guidelines
POA indicator for congenital conditions/anomalies and Q00-Q99 exceptionCongenital conditions and anomalies Assign “Y” for congenital conditions and anomalies except for categories Q00- Q99, Congenital anomalies, which are on the exempt list. Congenital conditions are always considered present on admission.
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026