R27.0 ICD-10-CM Code: Ataxia, unspecified
HCC Buddy Code Card
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FY 2026 Apr update / Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R99) / Symptoms and signs involving the nervous and musculoskeletal systems (R25-R29)
R27.0
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceAtaxia, unspecified
Loss of muscle coordination affecting movement and balance, resulting in clumsy or uncoordinated movements throughout the body.
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 R27.0 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for R27.0 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for R27.0 in this effective period.
Excludes 1
Official- ataxia following cerebrovascular disease (I69. with final characters -93)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for R27.0 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for R27.0 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for R27.0 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 R27.0 an HCC code?
No. R27.0 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
R27.0 is the ICD-10-CM diagnosis code for ataxia, unspecified. Loss of muscle coordination affecting movement and balance, resulting in clumsy or uncoordinated movements throughout the body. R27.0 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 symptoms and signs involving the nervous and musculoskeletal systems (r25-r29).
R27.0 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 distribution of ataxia (generalized vs. localized) and affected body parts.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for R27.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the distribution of ataxia (generalized vs. localized) and affected body parts
- •Consider documenting suspected etiology such as cerebellar, sensory, or vestibular causes if known
Excludes 1, Do NOT code together
- ataxia following cerebrovascular disease (I69. with final characters -93)