H49.21 ICD-10-CM Code: Sixth [abducent] nerve palsy, right eye
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FY 2026 Apr update / Diseases of the eye and adnexa (H00-H59) / Disorders of ocular muscles, binocular movement, accommodation and refraction (H49-H52)
H49.21
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSixth [abducent] nerve palsy, right eye
Paralysis of the sixth cranial nerve (abducent nerve) affecting the right eye, causing inability to move the right eye outward and resulting in inward eye deviation.
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 H49.21 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for H49.21 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for H49.21 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for H49.21 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for H49.21 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for H49.21 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for H49.21 in this effective period.
Buddy Documentation Tip
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is H49.21 an HCC code?
No. H49.21 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
- Code
- H49.21
- Description
- Sixth [abducent] nerve palsy, right eye
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF
- —
- Billable
- Yes
- Payment year
- 2026
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
H49.21 is the ICD-10-CM diagnosis code for sixth [abducent] nerve palsy, right eye. Paralysis of the sixth cranial nerve (abducent nerve) affecting the right eye, causing inability to move the right eye outward and resulting in inward eye deviation. H49.21 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of ocular muscles, binocular movement, accommodation and refraction (h49-h52).
H49.21 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.
The abducent nerve is the most commonly affected cranial nerve; document any underlying causes such as diabetes or increased intracranial pressure.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for H49.21 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The abducent nerve is the most commonly affected cranial nerve; document any underlying causes such as diabetes or increased intracranial pressure
- •Confirm right eye laterality is documented