Q28 ICD-10-CM Code: Other congenital malformations of circulatory system
HCC Buddy Code Card
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FY 2026 Apr update / Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0) / Congenital malformations of the circulatory system (Q20-Q28)
Q28
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceOther congenital malformations of circulatory system
Other congenital malformations of circulatory system
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
N/A—
Not mapped
ACA/HHS
N/A—
Not mapped
ESRD/PACE
N/A—
Not mapped
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for Q28 in this effective period.
Excludes 2
Official- congenital peripheral aneurysm (Q27.8)
- congenital pulmonary aneurysm (Q25.79)
- congenital retinal aneurysm (Q14.1)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for Q28 in this effective period.
Excludes 1
Official- congenital aneurysm NOS (Q27.8)
- congenital coronary aneurysm (Q24.5)
- ruptured cerebral arteriovenous malformation (I60.8)
- ruptured malformation of precerebral vessels (I72.0)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for Q28 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for Q28 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for Q28 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.
Coder workflow notes
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What This Code Means
Q28 is the ICD-10-CM diagnosis code for other congenital malformations of circulatory system. Q28 sits in the ICD-10-CM chapter for congenital malformations, deformations and chromosomal abnormalities (q00-qa0), within the section covering congenital malformations of the circulatory system (q20-q28).
Header codes like Q28 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 Q28'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 Q28 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.