Q00 Anencephaly and similar malformations
The ICD-10-CM code for Anencephaly and similar malformations is Q00 (FY2026). It is a non-billable category code — select a more specific code below for claims.
Classification
- Section
- Q00-Q07: Congenital malformations of the nervous system (Q00-Q07)
- Category Q00
- 4 codes (3 billable)
- FY2026 Status
- Stable since FY2024
Official Coding Guidelines
Assign Q00-QA1 when malformation/deformation/chromosomal abnormality documented17. Chapter 17: Congenital malformations, deformations, and chromosomal abnormalities (Q00-QA1) Assign an appropriate code(s) from categories Q00-QA1, Congenital malformations, deformations, and chromosomal abnormalities when a malformation/deformation or chromosomal abnormality is documented. A malformation/deformation/or chromosomal abnormality may be the principal/first-listed diagnosis on a record or a secondary diagnosis.
Chapter 17 codes usable throughout life; assign Q00-QA1 when diagnosedCodes from Chapter 17 may be used throughout the life of the patient. If a congenital malformation or deformity has been corrected, a personal history code should be used to identify the history of the malformation or deformity. Although present at birth, a malformation/deformation/or chromosomal abnormality may not be identified until later in life. Whenever the condition is diagnosed by the provider, it is appropriate to assign a code from codes Q00-QA1.
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026