Congenital malformations of great veins (Q26) ICD-10-CM
The Q26 code range covers congenital malformations of great veins with 10 ICD-10-CM diagnosis codes. 9 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the Q26 Range 10 codes · 9 billable
- Q26 Congenital malformations of great veinsNon-billable
- Q26.0 Congenital stenosis of vena cava
- Q26.1 Persistent left superior vena cava
- Q26.2 Total anomalous pulmonary venous connection
- Q26.3 Partial anomalous pulmonary venous connection
- Q26.4 Anomalous pulmonary venous connection, unspecified
- Q26.5 Anomalous portal venous connection
- Q26.6 Portal vein-hepatic artery fistula
- Q26.8 Other congenital malformations of great veins
- Q26.9 Congenital malformation of great vein, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the Q26 range.
Persistent Left Superior Vena Cava
Finding of the SUPERIOR VENA CAVA on the left instead of the usual right side of the ASCENDING AORTA. In bilateral superior vena cava it is found on both sides.
Scimitar Syndrome
An anomalous pulmonary venous return in which the right PULMONARY VEIN is not connected to the LEFT ATRIUM but to the INFERIOR VENA CAVA. Scimitar syndrome is named for the crescent- or Turkish sword-like shadow in the chest radiography and is often associated with hypoplasia of the right lung and right pulmonary artery, and dextroposition of the heart.
About the Q26 Code Range
The Q26 ICD-10 code section covers congenital malformations of great veins, which are structural abnormalities present at birth affecting major veins such as the vena cava and pulmonary veins. These codes help identify specific congenital vein conditions for accurate diagnosis and treatment planning.
This section includes codes like Q26.0, for congenital stenosis of the vena cava—commonly called inferior or superior vena cava stenosis—and Q26.1 for persistent left superior vena cava, an unusual vein connection often documented as “left superior caval vein persisting to coronary sinus.” Codes Q26.2 and Q26.3 identify total and partial anomalous pulmonary venous connections, respectively, which refer to abnormal drainage of pulmonary veins to systemic veins rather than the left atrium. Q26.4 specifies unspecified anomalous pulmonary venous connections, including terms like “Scimitar syndrome” or “pulmonary vein atresia.” Other less common malformations such as anomalous portal venous connections (Q26.5), portal vein-hepatic artery fistula (Q26.6), and various other great vein anomalies are coded under Q26.8 and Q26.9 for unspecified cases. Thus, the ICD-10 code for congenital malformations of great veins guides clinicians and coders in classifying diverse anatomical vein anomalies present from birth.
Questions About This Page
How many billable codes are in the Q26 range?
Of the 10 codes in this range, 9 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the Q26 range classify?
The range classifies congenital malformations of great veins. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
