G81.91 ICD-10-CM Code: Hemiplegia, unspecified affecting right dominant side
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 / Diseases of the nervous system (G00-G99) / Cerebral palsy and other paralytic syndromes (G80-G83)
G81.91
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceHemiplegia, unspecified affecting right dominant side
Weakness or loss of movement on one side of the body (right side) where the specific type (flaccid or spastic) is not specified, in a person whose right side is their dominant side.
Buddy Insight
Unspecified hemiplegia affecting the right dominant side identifies weakness or paralysis in a right-handed person's dominant extremities without specifying whether the presentation is flaccid or spastic.
CMS-HCC V28
MappedHCC 253
RAF 0.0
CMS-HCC V24
MappedHCC 103
RAF 0.447
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 103
RAF 0.0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for G81.91 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for G81.91 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for G81.91 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for G81.91 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for G81.91 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for G81.91 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for G81.91 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 G81.91 an HCC code?
Yes. G81.91 maps to Hemiplegia/Hemiparesis under the CMS-HCC V28 risk adjustment model (and Hemiplegia/Hemiparesis under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for G81.91
For G81.91to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed G81.91 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
G81.91 is the ICD-10-CM diagnosis code for hemiplegia, unspecified affecting right dominant side. Weakness or loss of movement on one side of the body (right side) where the specific type (flaccid or spastic) is not specified, in a person whose right side is their dominant side. G81.91 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering cerebral palsy and other paralytic syndromes (g80-g83).
Under the CMS-HCC V28 risk adjustment model, G81.91 maps to Hemiplegia/Hemiparesis (HCC 253) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, G81.91 mapped to the same category but with a base RAF weight of 0.447, V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Use when dominance is documented but muscle tone type is unclear. Because G81.91 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G81.91 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use when dominance is documented but muscle tone type is unclear
- •Request clarification from provider regarding flaccid versus spastic presentation
Clinical Significance
Unspecified hemiplegia affecting the right dominant side identifies weakness or paralysis in a right-handed person's dominant extremities without specifying whether the presentation is flaccid or spastic. While laterality and dominance are documented, the muscle tone classification is missing, which affects rehabilitation approach and prognosis. This code indicates partial documentation completeness with room for improvement.
Documentation Requirements
- ✓Documentation of hemiplegia affecting the right side
- ✓Right-hand dominance confirmed
- ✓Clinical findings supporting the diagnosis
- ✓Underlying etiology when known
- ✓Functional limitations and impact on dominant hand use
- ✓Active treatment plan
Commonly Confused Codes
- •G81.01 Flaccid hemiplegia, right dominant: use when flaccid type is documented
- •G81.11 Spastic hemiplegia, right dominant: use when spastic type is documented
- •G81.93 Hemiplegia, unspecified, right nondominant: right side but nondominant (left-handed person)
- •I69.351 Hemiplegia following cerebral infarction, right dominant: for stroke-related cases