Q26.8
Other congenital malformations of great veins
Q26.8 (also written Q268) is a billable ICD-10-CM diagnosis code for other congenital malformations of great veins. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 9 codes in category Q26 (Congenital malformations of great veins). The Alphabetic Index lists it under 19 entries. Its coding notes include 1 Excludes2 entry.
Guidelines tip
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Chapter 17 codes can be used for life. Manifestations that are an inherent part of a specifically coded anomaly are not coded separately. A corrected malformation is reported with a personal history code.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (1 note)
- inborn errors of metabolism (E70-E88)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Other clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Hospital CC
Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 9 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CInclusion terms
Conditions classified to this code.
- Absence of vena cava (inferior) (superior)
- Azygos continuation of inferior vena cava
- Persistent left posterior cardinal vein
- Scimitar syndrome
Notes
Also from chapter/block level (1 note)
- Codes from this chapter are not for use on maternal records
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 19 entries
- Absence (of) (organ or part) (complete or partial), superior vena cava, congenital
- Absence (of) (organ or part) (complete or partial), vein (peripheral) congenital NEC, great
- Absence (of) (organ or part) (complete or partial), vena cava (inferior) (superior), congenital
- Agenesis, vein (s) (peripheral), great NEC
- Agenesis, vena cava (inferior) (superior)
- Anomaly, anomalous (congenital) (unspecified type), vein (s) (peripheral), great, specified NEC
- Anomaly, anomalous (congenital) (unspecified type), venous return
- Atresia, atretic, vein NEC, great
- Atresia, atretic, vena cava (inferior) (superior)
- Azygos, continuation inferior vena cava
- Hypoplasia, hypoplastic, vein (s) (peripheral), great
- Hypoplasia, hypoplastic, vena cava (inferior) (superior)
Show 7 more
- Malformation (congenital), great, vein, specified type NEC
- Malposition, congenital, vein (s) (peripheral), great
- Malposition, congenital, vena cava (inferior) (superior)
- Persistence, persistent (congenital), left, posterior cardinal vein
- Persistence, persistent (congenital), sinus, venosus with imperfect incorporation in right auricle
- Scimitar syndrome
- Syndrome, scimitar