Q07.00

Arnold-Chiari syndrome without spina bifida or hydrocephalus

FY2027Chapter 17: Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders/Q00–Q07 Congenital malformations of the nervous system

BillableComplete code, valid to report

Q07.00 (also written Q0700) is a billable ICD-10-CM diagnosis code for arnold-Chiari syndrome without spina bifida or hydrocephalus. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 6 codes in category Q07 (Other congenital malformations of nervous system). The Alphabetic Index lists it under 1 entry. Its coding notes include 2 Excludes1 entries and 4 Excludes2 entries.

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.

Guidelines I.C.17Congenital malformations and genetic disordersRead the official text

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Inherited from Q07.0 Arnold-Chiari syndrome
  • Arnold-Chiari syndrome, type III (Q01.-)
  • Arnold-Chiari syndrome, type IV (Q04.8)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Inherited from Q07 Other congenital malformations of nervous system
  • congenital central alveolar hypoventilation syndrome (G47.35)
  • familial dysautonomia [Riley-Day] (G90.1)
  • neurofibromatosis (nonmalignant) (Q85.0-)
Also from chapter/block level (1 note)
Inherited from Chapter 17 Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
  • 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 Neuro Rehabilitation clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

Notes

Also from chapter/block level (1 note)
Inherited from Chapter 17 Congenital malformations, deformations, chromosomal abnormalities, and genetic disorders
  • Codes from this chapter are not for use on maternal records

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry