ICD-10-CM 2027 diagnosis code
Q03.0Malformations of aqueduct of Sylvius
Q03.0 is a valid, billable ICD-10-CM code for malformations of aqueduct of sylvius. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About Q03.0
Q03.0 is the ICD-10-CM diagnosis code for malformations of aqueduct of Sylvius. It belongs to category Q03 (congenital hydrocephalus), block Q00-Q07 (congenital malformations of the nervous system) and chapter 17 (congenital malformations, deformations, chromosomal abnormalities, and genetic disorders). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within Q03 (congenital hydrocephalus), Q03.0 is specifically for malformations of aqueduct of Sylvius. Related codes cover atresia of foramina of Magendie and Luschka (Q03.1), other congenital hydrocephalus (Q03.8) and unspecified (Q03.9).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 091 (Other Disorders of Nervous System with MCC, relative weight 1.7046), DRG 092 (Other Disorders of Nervous System with CC, relative weight 1.0239), DRG 093 (Other Disorders of Nervous System without CC/MCC, relative weight 0.7783), DRG 791 (Prematurity with Major Problems, relative weight 4.1075) and DRG 793 (Full Term Neonate with Major Problems, relative weight 4.2195), in MDC 01 (Diseases and Disorders of the Nervous System) and MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It is exempt from present-on-admission (POA) reporting, so no POA indicator is required.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 742.3 (congenital hydrocephalus).
Coding notes
- Anomaly of aqueduct of Sylvius
- Obstruction of aqueduct of Sylvius, congenital
- Stenosis of aqueduct of Sylvius
Notes that apply from higher levels
Instructions written at a parent level also apply to Q03.0.
› From Q03 Congenital hydrocephalus
Broader instructions also apply from Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders.
Alphabetic index entries
8 entriesTerms in the official ICD-10-CM index that lead to Q03.0.
- 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)
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 01 · Diseases and Disorders of the Nervous System
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
MDC 15 · Newborns and Other Neonates with Conditions Originating in the Perinatal Period
ICD-9-CM equivalent
Converter →- 742.3Congenital hydrocephalusapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about Q03.0
Is Q03.0 billable?
- Yes. Q03.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q03.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q03.0 as a principal diagnosis.
Is Q03.0 a CC or MCC?
- No. Q03.0 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does Q03.0 group to?
- Q03.0 is used in the MS-DRG v44.0 logic for MS-DRG 091 (Other Disorders of Nervous System with MCC), MS-DRG 092 (Other Disorders of Nervous System with CC), MS-DRG 093 (Other Disorders of Nervous System without CC/MCC), MS-DRG 791 (Prematurity with Major Problems) and MS-DRG 793 (Full Term Neonate with Major Problems). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for Q03.0?
- The CMS General Equivalence Mappings map Q03.0 to ICD-9-CM 742.3.