Q03.1

Atresia of foramina of Magendie and Luschka

Risk-adjusting (HCC)Billable code

HCC risk adjustment mapping

CMS-HCC V28

HCC182

Spinal Cord Disorders/Injuries

CMS-HCC ESRD V24

HCC72

Spinal Cord Disorders/Injuries

RxHCC V08

RXHCC155

Spinal Cord Disorders

Coding notes

Excludes 1 never coded together · Excludes 2 may co-exist

This code · Q03.1

Synonyms

Dandy-Walker syndrome

Inherited from Q03Congenital hydrocephalus

Includes

hydrocephalus in newborn

Excludes 1

Arnold-Chiari syndrome, type II (Q07.0-) acquired hydrocephalus (G91.-) hydrocephalus due to congenital toxoplasmosis (P37.1) hydrocephalus with spina bifida (Q05.0-Q05.4)

Inherited from chapter 17Congenital malformations, deformations and chromosomal abnormalities

Excludes 2

inborn errors of metabolism (E70-E88)

Note

Codes from this chapter are not for use on maternal records

Official Guidelines for Q03.1

FY 2026 ›

I.C.17Chapter-specific guidanceChapter 17: Congenital malformations, deformations, and chromosomal abnormalities (Q00-QA1)

Sections that reference Q03.1

IV.QEncounters for routine health screeningsOutpatient services
… Congenital conditions and anomalies Assign “Y” for congenital conditions and anomalies except for categories Q00- Q99, Congenital anomalies, which are on the exempt list. …

Sections whose FY 2026 text names Q03.1, its Q03 category, or a range containing it — the chapter guidance above is the authoritative source.

Find Q03.1 in the alphabetic index

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