R51.9 ICD-10-CM Code: Headache, unspecified
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99) / General symptoms and signs (R50-R69)
R51.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceHeadache, unspecified
A headache where the specific type, location, or cause is not documented or identified.
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
Basket needed
Code Book Path
Inclusion Terms
Official- Facial pain NOS
Excludes 2
Official- atypical face pain (G50.1)
- migraine and other headache syndromes (G43-G44)
- trigeminal neuralgia (G50.0)
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for R51.9 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for R51.9 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for R51.9 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for R51.9 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for R51.9 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 R51.9 an HCC code?
No. R51.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
Coder workflow notes
Get the V28 RAF + MEAT cheat sheet
One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.
Free PDF. No card. Unsubscribe anytime.
This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).
What This Code Means
R51.9 is the ICD-10-CM diagnosis code for headache, unspecified. A headache where the specific type, location, or cause is not documented or identified. R51.9 sits in the ICD-10-CM chapter for symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (r00-r99), within the section covering general symptoms and signs (r50-r69).
R51.9 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.
This is a non-specific code; attempt to obtain more detailed information about headache characteristics from the provider.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for R51.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.