2026 ICD-10-CM Diagnosis Code Q03.0Malformations of aqueduct of Sylvius

ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q03

ICD-10-CM Q03.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q03.0 is a billable ICD-10-CM diagnosis code for malformations of aqueduct of Sylvius. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.

Code Identity

ICD-10-CM Code
Q03.0
Billable Status
Yes — Valid for Submission
Code Describes
Malformations of aqueduct of Sylvius
Short Description
Malformations of aqueduct of Sylvius
Same as the full description in the CMS dataset.
Parent Code
Q03
Congenital hydrocephalus

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ00-Q07Congenital malformations of the nervous system
CategoryQ03Congenital hydrocephalus
This CodeQ03.0Malformations of aqueduct of Sylvius

Present on Admission (POA)Billing

Q03.0 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.

  • Aqueduct of Sylvius anomaly
  • Atresia of aqueduct of Sylvius
  • Congenital obstruction of aqueduct of Sylvius
  • Congenital stenosis of aqueduct of Sylvius
  • Hydrocephalus associated with congenital aqueduct stenosis
  • Hydrocephalus with anomaly of aqueduct of Sylvius
  • Spina bifida with stenosis of aqueduct of Sylvius

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Anomaly of aqueduct of Sylvius
  • Obstruction of aqueduct of Sylvius, congenital
  • Stenosis of aqueduct of Sylvius

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.

    • Anomaly, anomalous(congenital) (unspecified type)
      • aqueduct of Sylvius
    • Atresia, atretic
      • aqueduct of Sylvius
    • Hydrocephalus(acquired) (external) (internal) (malignant) (recurrent)
      • aqueduct Sylvius stricture
    • Obstruction, obstructed, obstructive
      • aqueduct of Sylvius
        • congenital
    • Occlusion, occluded
      • aqueduct of Sylvius
        • congenital
    • Septum, septate(congenital)
      • aqueduct of Sylvius
    • Stenosis, stenotic(cicatricial)
      • aqueduct of Sylvius (congenital)
    • Stricture
      • aqueduct of Sylvius (congenital)

Clinical ClassificationClinical

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

CCSR MAL004
Nervous system congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Congenital Hydrocephalus

    hydrocephalus that is present at birth.

Patient EducationClinical

Hydrocephalus

Hydrocephalus is the buildup of too much cerebrospinal fluid in the brain. Normally, this fluid cushions your brain. When you have too much, though, it puts harmful pressure on your brain.

Read the full article at MedlinePlus

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

Convert Q03.0 to ICD-9-CMHistory

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

ICD-9-CM
742.3 Congenital hydrocephalus
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 Q03.0Overview

Is Q03.0 (Congenital hydrocephalus) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malformations of aqueduct of Sylvius on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is Q03.0 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 malformations of aqueduct of Sylvius on inpatient claims.

What is the ICD-9 equivalent of Q03.0?

Under the General Equivalence Mappings, malformations of aqueduct of Sylvius converts to ICD-9-CM 742.3 (congenital hydrocephalus). 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.