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Q04 ICD-10-CM Code: Other congenital malformations of brain

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FY 2026 Apr update / Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0) / Congenital malformations of the nervous system (Q00-Q07)

Q04

Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidance

Other congenital malformations of brain

Other congenital malformations of brain

CMS-HCC V28

0

0

RAF 0

CMS-HCC V24

0

0

RAF 0

ACA/HHS

0

0

RAF 0

ESRD/PACE

0

0

RAF 0

RXHCC

0

0

RAF 0

Code Trumping

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Code Book Path

Official
Q0Congenital malformations of the nervous system (Q00-Q07)
Q04Other congenital malformations of brain

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for Q04 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for Q04 in this effective period.

Related Child Codes

Official
Q04.0Congenital malformations of corpus callosum
Q04.1Arhinencephaly
Q04.2Holoprosencephaly
Q04.3Other reduction deformities of brain
Q04.4Septo-optic dysplasia of brain

Includes

Official

ICD-10-CM does not list Includes notes for Q04 in this effective period.

Excludes 1

Official
  • cyclopia (Q87.0)
  • macrocephaly (Q75.3)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for Q04 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for Q04 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for Q04 in this effective period.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

What This Code Means

Q04 is the ICD-10-CM diagnosis code for other congenital malformations of brain. Q04 sits in the ICD-10-CM chapter for congenital malformations, deformations and chromosomal abnormalities (q00-qa0), within the section covering congenital malformations of the nervous system (q00-q07).

Header codes like Q04 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at Q04's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q04 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Excludes 1, Do NOT code together

Child Codes

Code Hierarchy

Q04Other congenital malformations of brain
Q04Other congenital malformations of brain

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