Q75.021 ICD-10-CM Code: Coronal craniosynostosis, unilateral
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FY 2026 Apr update / Congenital malformations, deformations and chromosomal abnormalities (Q00-QA0) / Congenital malformations and deformations of the musculoskeletal system (Q65-Q79)
Q75.021
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCoronal craniosynostosis, unilateral
A birth defect where the coronal suture (the seam across the front of the skull) fuses prematurely on one side, causing asymmetrical head shape.
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
Official- Non-deformational anterior plagiocephaly
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for Q75.021 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for Q75.021 in this effective period.
Excludes 1
Official- dolichocephaly (Q67.2)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for Q75.021 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for Q75.021 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for Q75.021 in this effective period.
Buddy Documentation Tip
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.
Is Q75.021 an HCC code?
No. Q75.021 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
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This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
Q75.021 is the ICD-10-CM diagnosis code for coronal craniosynostosis, unilateral. A birth defect where the coronal suture (the seam across the front of the skull) fuses prematurely on one side, causing asymmetrical head shape. Q75.021 sits in the ICD-10-CM chapter for congenital malformations, deformations and chromosomal abnormalities (q00-qa0), within the section covering congenital malformations and deformations of the musculoskeletal system (q65-q79).
Q75.021 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Verify unilateral involvement is documented; coronal synostosis often causes anterior plagiocephaly.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for Q75.021 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify unilateral involvement is documented; coronal synostosis often causes anterior plagiocephaly
- •Distinguish from bilateral coronal (Q75.022) which affects both sides and causes brachycephaly