2027 ICD-10-CM Diagnosis Code Q05.1Thoracic spina bifida with hydrocephalus
ICD-10-CM Codes›Q00-Q99›Q00-Q07›Q05
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 182
- POA Exempt
- Chronic Condition
Q05.1 is a billable ICD-10-CM diagnosis code for thoracic spina bifida with hydrocephalus. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 91 through 93, 791, 793. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 65 closely related codes. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system congenital anomalies.
For Medicare Advantage risk adjustment, Q05.1 maps to CMS-HCC Category 182 (Spinal Cord Disorders/Injuries) under the V28 model, adding a risk factor of about 0.478 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Present on Admission (POA)Billing
Q05.1 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Congenital malformations of the nervous system (Q00-Q07).
Medicare Risk Adjustment (HCC)Billing
Q05.1 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Cervical spina bifida with hydrocephalus
- Cervical spina bifida with hydrocephalus - open
- Cervicothoracic spina bifida aperta
- Cervicothoracic spina bifida aperta with hydrocephalus
- Lumbar spina bifida with hydrocephalus
- Lumbar spina bifida with hydrocephalus - closed
- Spina bifida aperta of cervical spine
- Spina bifida aperta of thoracic spine
- Spina bifida with hydrocephalus - closed
- Spina bifida with hydrocephalus - open
- Thoracic spina bifida with hydrocephalus
- Thoracic spina bifida with hydrocephalus - closed
- Thoracic spina bifida with hydrocephalus - open
- Thoracolumbar spina bifida with hydrocephalus - closed
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to Q05.1: its own notes plus those printed at Q05 and Chapter 17. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- hydromeningocele (spinal)
- meningocele (spinal)
- meningomyelocele
- myelocele
- myelomeningocele
- rachischisis
- spina bifida (aperta)(cystica)
- syringomyelocele
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Dorsal spina bifida with hydrocephalus
- Thoracolumbar spina bifida with hydrocephalus
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
Notes
General instructions on how these codes are used.
- Codes from this chapter are not for use on maternal records
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name Q05.1, its category, or a range that includes it.
Excludes1 4
These codes carry an Excludes1 note naming Q05.1: they are not reported together with it, unless the two conditions are unrelated.
- G91 Hydrocephalusspina bifida with hydrocephalus (Q05.-) names Q05.-, which includes this code
- Q76.0 Spina bifida occultameningocele (spinal) (Q05.-) names Q05.-, which includes this code
- Q76.0 Spina bifida occultaspina bifida (aperta) (cystica) (Q05.-) names Q05.-, which includes this code
- Q03 Congenital hydrocephalus
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Spinal Dysraphism
congenital defects of closure of one or more vertebral arches, which may be associated with malformations of the spinal cord, nerve roots, congenital fibrous bands, lipomas, and congenital cysts. these malformations range from mild (e.g., spina bifida occulta) to severe, including rachischisis where there is complete failure of neural tube and spinal cord fusion, resulting in exposure of the spinal cord at the surface. spinal dysraphism includes all forms of spina bifida. the open form is called spina bifida cystica and the closed form is spina bifida occulta. (from joynt, clinical neurology, 1992, ch55, p34)
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 Q05.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About Q05.1Overview
What is the ICD-10 code for thoracic spina bifida with hydrocephalus?
The ICD-10-CM code for thoracic spina bifida with hydrocephalus is Q05.1 (sometimes written as Q051). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is Q05.1 (Spina bifida) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report thoracic spina bifida with hydrocephalus on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does Q05.1 group to?
When thoracic spina bifida with hydrocephalus is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 91, 92, 93, with relative weights from 0.7783 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is Q05.1 a CC or MCC?
CMS lists Q05.1 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 65 closely related codes in its exclusion list.
Is Q05.1 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 thoracic spina bifida with hydrocephalus on inpatient claims. The code appears in the Congenital malformations of the nervous system (Q00-Q07) range of the CMS exempt list.
What HCC is Q05.1?
Q05.1 (thoracic spina bifida with hydrocephalus) maps to CMS-HCC Category 182 (Spinal Cord Disorders/Injuries), commonly written as HCC 182, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 72 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 155.
Does Q05.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, Q05.1 adds a risk adjustment factor of about 0.478 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.270 to 0.478 depending on the payment segment). A more severe related category (HCC 180, HCC 181, HCC 191, and HCC 192) supersedes it when both are reported. See the full factor table on the HCC 182 category page.
