G44.81 ICD-10-CM Code: Hypnic headache
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)
G44.81
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceHypnic headache
A headache that occurs during sleep or upon waking, typically affecting older adults and occurring multiple times per week.
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 G44.81 in this effective period.
Excludes 2
Official- headache with orthostatic or positional component, not elsewhere classified (R51.0)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for G44.81 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for G44.81 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for G44.81 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for G44.81 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for G44.81 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 G44.81 an HCC code?
No. G44.81 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
G44.81 is the ICD-10-CM diagnosis code for hypnic headache. A headache that occurs during sleep or upon waking, typically affecting older adults and occurring multiple times per week. G44.81 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering episodic and paroxysmal disorders (g40-g47).
G44.81 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.
Document the temporal relationship to sleep and confirm headaches occur during sleep periods.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G44.81 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the temporal relationship to sleep and confirm headaches occur during sleep periods
- •Note the frequency and pattern of nocturnal headache episodes