2026 ICD-10-CM Diagnosis Code Q26.1Persistent left superior vena cava

ICD-10-CM Codes›Q00-Q99›Q20-Q28›Q26

ICD-10-CM Q26.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q26.1 is a billable ICD-10-CM diagnosis code for persistent left superior vena cava. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 306 through 307. The code is exempt from POA reporting. Coders also document this condition as left superior caval vein persisting to coronary sinus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Cardiac and circulatory congenital anomalies.

Code Identity

ICD-10-CM Code
Q26.1
Billable Status
Yes — Valid for Submission
Code Describes
Persistent left superior vena cava
Short Description
Persistent left superior vena cava
Same as the full description in the CMS dataset.
Parent Code
Q26
Congenital malformations of great veins

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ20-Q28Congenital malformations of the circulatory system
CategoryQ26Congenital malformations of great veins
This CodeQ26.1Persistent left superior vena cava

Present on Admission (POA)Billing

Q26.1 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Left superior caval vein persisting to coronary sinus
  • Left superior caval vein persisting to coronary sinus and then to right sided atrium
  • Left superior caval vein persisting to left sided atrium
  • Left superior caval vein persisting to right atrium and left atrium
  • Left superior caval vein persisting to right sided atrium
  • Persistent left superior vena cava
  • Persistent left superior vena cava connecting through coronary sinus to left sided atrium

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Malformation(congenital)
      • great
        • vein
          • persistent left superior vena cava
    • Persistence, persistent(congenital)
      • left
        • superior vena cava

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL001
Cardiac and circulatory congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • 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.

Patient EducationClinical

Aneurysms

An aneurysm is a bulge or "ballooning" in the wall of an artery. Arteries are blood vessels that carry oxygen-rich blood from the heart to other parts of the body. If an aneurysm grows large, it can burst and cause dangerous bleeding or even death.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q26.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
747.49 Great vein anomaly NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q26.1Overview

Is Q26.1 (Congenital malformations of great veins) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report persistent left superior vena cava on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does Q26.1 group to?

When persistent left superior vena cava is the principal diagnosis on an inpatient stay, it groups to MS-DRG 306, 307, with relative weights from 0.9132 to 1.5758 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q26.1 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for persistent left superior vena cava on inpatient claims.

What is the ICD-9 equivalent of Q26.1?

Under the General Equivalence Mappings, persistent left superior vena cava converts to ICD-9-CM 747.49 (great vein anomaly NEC). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.