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Q04.5

Q04.5Megalencephaly

Billable / specific codeICD-10-CMPOA exempt

Q04.5 is a billable, specific ICD-10-CM code for megalencephaly. It is valid for submission on a claim.

Risk adjustment

Q04.5 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 182 Spinal Cord Disorders/Injuries0.478 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

Q04.5 is named in 3 Medicare coverage policies 3 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A54111Billing and Coding: Speech Language Pathology (SLP) Services: Communication Disorders
  • A56612Billing and Coding: CT of the Head
  • A57204Billing and Coding: MRI and CT Scans of the Head and Neck

How Q04.5 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to Q04.5.

  • Hemimegalencephaly
  • Megalencephaly

Related codes at this level

Codes that share Q04. If Q04.5 is not quite right, the correct code is usually one of these.

Questions about Q04.5

Is Q04.5 a billable ICD-10-CM code?
Yes. Q04.5 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does Q04.5 sit in the tabular list?
Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0), in the block Congenital malformations of the nervous system (Q00-Q07).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.