G51.8 ICD-10-CM Code: Other disorders of facial nerve
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FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Nerve, nerve root and plexus disorders (G50-G59)
G51.8
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther disorders of facial nerve
This code describes various disorders affecting the facial nerve that don't fit into other specific categories, such as facial nerve compression, irritation, or dysfunction from causes other than Bell's palsy or trauma. These conditions can affect facial movement, sensation, or function on one or both sides of the face.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for G51.8 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for G51.8 in this effective period.
Related Child Codes
Includes
Official- disorders of 7th cranial nerve
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for G51.8 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for G51.8 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for G51.8 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for G51.8 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 G51.8 an HCC code?
No. G51.8 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
G51.8 is the ICD-10-CM diagnosis code for other disorders of facial nerve. This code describes various disorders affecting the facial nerve that don't fit into other specific categories, such as facial nerve compression, irritation, or dysfunction from causes other than Bell's palsy or trauma. These conditions can affect facial movement, sensation, or function on one or both sides of the face. G51.8 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering nerve, nerve root and plexus disorders (g50-g59).
G51.8 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.
Use this code only when the facial nerve disorder is not better described by more specific codes like G51.0 (Bell's palsy) or G51.3 (Clonic hemifacial spasm); always check for a more specific diagnosis first.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G51.8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when the facial nerve disorder is not better described by more specific codes like G51.0 (Bell's palsy) or G51.3 (Clonic hemifacial spasm); always check for a more specific diagnosis first
- •Document the underlying cause or specific manifestation of the facial nerve disorder in the medical record to support medical necessity and ensure accurate coding