Anencephaly and similar malformations (Q00) ICD-10-CM
The Q00 code range covers anencephaly and similar malformations with 4 ICD-10-CM diagnosis codes. 3 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the Q00 Range 4 codes · 3 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the Q00 range.
Anencephaly
A malformation of the nervous system caused by failure of the anterior neuropore to close. Infants are born with intact spinal cords, cerebellums, and brainstems, but lack formation of neural structures above this level. The skull is only partially formed but the eyes are usually normal. This condition may be associated with folate deficiency. Affected infants are only capable of primitive (brain stem) reflexes and usually do not survive for more than two weeks. (From Menkes, Textbook of Child Neurology, 5th ed, p247)
About the Q00 Code Range
The ICD-10 code section Q00 covers anencephaly and related neural tube defects, which are serious congenital malformations affecting the brain and spinal cord development.
This section includes specific codes like Q00.0 for anencephaly, a condition also known by terms such as congenital brain aplasia, acrania, and holoanencephaly, characterized by absence of major parts of the brain and skull. Code Q00.1 denotes craniorachischisis, where both the brain and spinal cord remain open due to failed closure of the neural tube. Meanwhile, Q00.2 identifies iniencephaly, a malformation involving severe neck and spinal defects often linked with abnormal cervical vertebrae positioning. These codes are crucial for accurately recording and reporting congenital nervous system anomalies. Knowing the synonyms helps medical coders correctly assign the ICD-10 code for conditions like acrania or craniorachischisis when documentation uses alternate terms, ensuring precise diagnosis coding and data capture.
Questions About This Page
How many billable codes are in the Q00 range?
Of the 4 codes in this range, 3 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the Q00 range classify?
The range classifies anencephaly and similar malformations. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
