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

Compare with another code for Q26.1Check this code on a claim

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Risk adjustment
RxHCC V08 category 191

What these terms mean →

Billable · FY2027A valid, specific ICD-10-CM code, reportable for dates of service in FY2027.

What you need to know

Source: CMS/NCHS Official ICD-10-CM tabular notes, quoted. From the CMS/NCHS tabular list for the release in force. A note the category or block publishes applies to this code too, and is marked with where it comes from.

The tabular list publishes no instructional note for this code itself.

Where it sits Source: CMS/NCHS

Under:Chapter 17: Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-QA1) (Q00-QA1)Q20-Q28 Congenital malformations of the circulatory systemQ26 Congenital malformations of great veins

CompareCheck ClaimView Related Codes

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v44, Appendix B.

  • MS-DRG 306 — CARDIAC CONGENITAL AND VALVULAR DISORDERS WITH MCC (MDC 05)
  • MS-DRG 307 — CARDIAC CONGENITAL AND VALVULAR DISORDERS WITHOUT MCC (MDC 05)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Don’t confuse Q26.1 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of Q26.1 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

  • Q26.4— Specificity relationship (Review)

    Overlapping diagnoses in the same category.

    Overlapping codes in the same category — the documentation decides which is the more specific fit.

    What moves you there: A record that documents no more than “Anomalous pulmonary venous connection, unspecified” takes Q26.4; specificity in the record moves it back here.

    Full comparison: Q26.1 vs Q26.4 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Coding context

Guidelines, coding notes, decision aids, relationships (with MS-DRG and CCSR classification), hierarchy, HCC, coverage and the context map: what a coder reaches for after the core. Each section names whether it is official source data, a MedCoder-derived relationship or MedCoder editorial.

Code Overview

Persistent left superior vena cava is a billable ICD-10-CM diagnosis code (Q26.1).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

  • CC as a secondary diagnosis (FY2027). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder-derived relationships — computed from published CMS and AHRQ datasets

Other codes that name Q26.1 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes2 note: P29 — Cardiovascular disorders originating in the perinatal period (via Q26.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 2 Code Also instructions across 2 chapters: I27.21 — Secondary pulmonary arterial hypertension (via Q26.-), Z71.87 — Encounter for pediatric-to-adult transition counseling (via Q26.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2027)

Potential MS-DRG participation — not a DRG assignment.

FY2027 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 9 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 306 (MDC 05), DRG 307 (MDC 05).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):MAL001 — Cardiac and circulatory congenital anomalies (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

Q26.0 — Congenital stenosis of vena cava, Q26.8 — Other congenital malformations of great veins, Q27.30 — Arteriovenous malformation, site unspecified, Q27.4 — Congenital phlebectasia, Q28.0 — Arteriovenous malformation of precerebral vessels, Q28.1 — Other malformations of precerebral vessels, Q28.8 — Other specified congenital malformations of circulatory system, Q28.9 — Congenital malformation of circulatory system, unspecified

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Cardiac and circulatory congenital anomalies).

Q25.48 — Anomalous origin of subclavian artery, Q25.49 — Other congenital malformations of aorta, Q25.5 — Atresia of pulmonary artery, Q25.6 — Stenosis of pulmonary artery, Q25.71 — Coarctation of pulmonary artery, Q25.72 — Congenital pulmonary arteriovenous malformation, Q25.79 — Other congenital malformations of pulmonary artery, Q25.8 — Other congenital malformations of other great arteries, Q25.9 — Congenital malformation of great arteries, unspecified, Q26.0 — Congenital stenosis of 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, Q27.0 — Congenital absence and hypoplasia of umbilical artery, Q27.1 — Congenital renal artery stenosis, Q27.2 — Other congenital malformations of renal artery, +87 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Malformation”, “Persistence, persistent”; these codes share that main term but sit in a different category of the Tabular List.

Q25.45 — Double aortic arch (double aortic arch), Q25.46 — Tortuous aortic arch (convolutions, aortic arch), Q25.47 — Right aortic arch (right aortic arch), Q25.49 — Other congenital malformations of aorta (aorta, specified type NEC), Q25.5 — Atresia of pulmonary artery (pulmonary, artery, atresia), Q25.6 — Stenosis of pulmonary artery (pulmonary, artery, stenosis), Q25.72 — Congenital pulmonary arteriovenous malformation (pulmonary, arteriovenous), Q25.79 — Other congenital malformations of pulmonary artery (pulmonary, artery, specified type NEC), Q25.8 — Other congenital malformations of other great arteries (great, artery, specified type NEC), Q25.9 — Congenital malformation of great arteries, unspecified (great, artery), Q27.2 — Other congenital malformations of renal artery (renal artery), Q27.30 — Arteriovenous malformation, site unspecified (arteriovenous, aneurysmatic), Q27.31 — Arteriovenous malformation of vessel of upper limb (arteriovenous, aneurysmatic, peripheral, upper limb), Q27.32 — Arteriovenous malformation of vessel of lower limb (arteriovenous, aneurysmatic, peripheral, lower limb), Q27.33 — Arteriovenous malformation of digestive system vessel (arteriovenous, aneurysmatic, peripheral, digestive system, congenital), Q27.34 — Arteriovenous malformation of renal vessel (arteriovenous, aneurysmatic, peripheral, renal vessel), Q27.39 — Arteriovenous malformation, other site (arteriovenous, aneurysmatic, peripheral, other specified site), Q27.8 — Other specified congenital malformations of peripheral vascular system (peripheral vascular system, specified type NEC), Q27.9 — Congenital malformation of peripheral vascular system, unspecified (peripheral vascular system), Q28.0 — Arteriovenous malformation of precerebral vessels (arteriovenous, aneurysmatic, precerebral vessels), +181 more

Contextual Map

Every relationship of Q26.1 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run Q26.1 with these 3 related codes in Claim Check

Hierarchy

Referenced by Excludes2 notes

Referenced by Code Also instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 05 — Diseases and Disorders of the Circulatory System[MDC crossing]: “Diseases and Disorders of the Circulatory System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 15,708 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2027

Index entries

  • Malformation (congenital), great, vein, persistent left superior vena cava[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027
  • Persistence, persistent (congenital), left, superior vena cava[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2027

Nearest codes (9)

Change history

  • FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Reference

Index terms and tables, published questions and FAQ, every source behind this page with its release and checksum, the date-of-service check and the complete change history.

Indexed Clinical Terms (2)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2027 tabular list, index and tables, effective October 1, 2026 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v44.0 (October 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v44 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder-derived relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder editorial explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Labels on this page: Official source data · MedCoder-derived relationship · MedCoder editorial explanation. How to read the labels · All data sources and release dates · CMS coding rules

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "Q26.1 — Persistent left superior vena cava." ICD-10-CM FY2027. https://medcoder.ai/icd10/code/q26.1-persistent-left-superior-vena-cava

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Persistent left superior vena cava

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027, and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to Q26.1 in its code family, with their registry titles.

View all codes in the Q26 family