What is ICD-10 code G81.00?

G81.00 is the ICD-10-CM diagnosis code for Flaccid hemiplegia affecting unspecified side. Weakness or paralysis affecting one side of the body with floppy, loose muscle tone when the affected side is not specified. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G81.00 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G81.00 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. G81.00 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. G81.00 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for G81.00?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For G81.00, V28 maps to Hemiplegia/Hemiparesis at RAF 0.387 while V24 mapped to Hemiplegia/Hemiparesis at RAF 0.437. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting G81.00?

Flaccid hemiplegia indicates low muscle tone; distinguish from spastic hemiplegia which has high muscle tone If the dominant or non-dominant side is documented, use the more specific codes G81.01 or G81.02 Because G81.00 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM G81.00: Flaccid hemiplegia

ICD-10-CM Code View

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Code lookupG81.00Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Cerebral palsy and other paralytic syndromes (G80-G83)

G81.00

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Flaccid hemiplegia affecting unspecified side

Weakness or paralysis affecting one side of the body with floppy, loose muscle tone when the affected side is not specified.

Buddy Insight

Flaccid hemiplegia affecting an unspecified side represents significant neurological deficit with loss of muscle tone on one side of the body, typically as a sequela of stroke or brain injury.

CMS-HCC V28

Mapped

HCC 253

Hemiplegia/Hemiparesis

RAF 0.387

CMS-HCC V24

Mapped

HCC 103

Hemiplegia/Hemiparesis

RAF 0.437

ACA/HHS

Mapped

HCC 150

HHS-HCC 150

Varies by metal level

ESRD/PACE

Mapped

HCC 103

Hemiplegia/Hemiparesis

RAF 0.071

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

G81Hemiplegia and hemiparesis

G81.0Flaccid hemiplegia

G81.00Flaccid hemiplegia affecting unspecified side

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for G81.00 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G81.00 in this effective period.

Related Child Codes

Official

G81.01Flaccid hemiplegia affecting right dominant side

G81.02Flaccid hemiplegia affecting left dominant side

G81.03Flaccid hemiplegia affecting right nondominant side

G81.04Flaccid hemiplegia affecting left nondominant side

Includes

Official

ICD-10-CM does not list Includes notes for G81.00 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G81.00 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G81.00 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G81.00 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G81.00 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation of hemiplegia or hemiparesis with flaccid (low tone) presentation

Underlying etiology (stroke, traumatic brain injury, tumor, etc.)

Neurological examination findings confirming flaccid tone

Functional impact on mobility and activities of daily living

MEAT Support

HCC Buddy guidance

Documentation of hemiplegia or hemiparesis with flaccid (low tone) presentation

Underlying etiology (stroke, traumatic brain injury, tumor, etc.)

Neurological examination findings confirming flaccid tone

Functional impact on mobility and activities of daily living

Audit Caution

HCC Buddy guidance

Not querying for laterality and dominance, which would allow a more specific 5th character code

Confusing flaccid (low tone, floppy) with spastic (high tone, stiff) presentations

Using G81 codes instead of I69 sequelae codes when the hemiplegia is documented as resulting from a cerebrovascular accident

Coding hemiplegia during the acute stroke episode — use the acute stroke code with the appropriate 5th/6th character instead

Common Mistakes

HCC Buddy guidance

G81.10 Spastic hemiplegia affecting unspecified side — spastic has high muscle tone; flaccid has low tone

G81.90 Hemiplegia, unspecified affecting unspecified side — use when neither flaccid nor spastic is documented

G81.01-G81.04 Flaccid hemiplegia with laterality — use when dominant/nondominant side is specified

I69.051-I69.054 Hemiplegia following cerebrovascular disease — use the I69 sequelae codes when hemiplegia is specifically documented as a sequela of stroke

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is G81.00 an HCC code?

Yes. G81.00 (Flaccid hemiplegia affecting unspecified side) maps to Hemiplegia/Hemiparesis under the CMS-HCC V28 risk adjustment model (and Hemiplegia/Hemiparesis under V24), with a community non-dual aged RAF of 0.387. It is billable for payment year 2026.

Coder answer: G81.00 is billable and maps to V28 HCC 253, Hemiplegia/Hemiparesis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: G81.00
Description: Flaccid hemiplegia affecting unspecified side
HCC (V28): HCC 253 — Hemiplegia/Hemiparesis
RAF: 0.387
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 253, Hemiplegia/Hemiparesis

0.387

V24HCC 103, Hemiplegia/Hemiparesis

0.437

ESRDHCC 103, Hemiplegia/Hemiparesis

0.071

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work G81.00 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for G81.00

For G81.00 to 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 G81.00 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

G81.00 is the ICD-10-CM diagnosis code for flaccid hemiplegia affecting unspecified side. Weakness or paralysis affecting one side of the body with floppy, loose muscle tone when the affected side is not specified. G81.00 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, G81.00 maps to Hemiplegia/Hemiparesis (HCC 253) with a community, non-dual, aged base RAF weight of 0.387. Under the older V24 model, G81.00 mapped to the same category but with a base RAF weight of 0.437, 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.

Flaccid hemiplegia indicates low muscle tone; distinguish from spastic hemiplegia which has high muscle tone. Because G81.00 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 G81.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Flaccid hemiplegia indicates low muscle tone; distinguish from spastic hemiplegia which has high muscle tone
•If the dominant or non-dominant side is documented, use the more specific codes G81.01 or G81.02

Clinical Significance

Flaccid hemiplegia affecting an unspecified side represents significant neurological deficit with loss of muscle tone on one side of the body, typically as a sequela of stroke or brain injury. This condition profoundly impacts independence, mobility, and quality of life, requiring ongoing rehabilitation, assistive devices, and caregiver support. Accurate coding is essential for predicting healthcare resource needs.

Documentation Requirements

✓Documentation of hemiplegia or hemiparesis with flaccid (low tone) presentation
✓Underlying etiology (stroke, traumatic brain injury, tumor, etc.)
✓Neurological examination findings confirming flaccid tone
✓Functional impact on mobility and activities of daily living
✓Current treatment plan (physical therapy, occupational therapy, assistive devices)
✓Status as ongoing condition being actively managed

Commonly Confused Codes

•G81.10 Spastic hemiplegia affecting unspecified side: spastic has high muscle tone; flaccid has low tone
•G81.90 Hemiplegia, unspecified affecting unspecified side: use when neither flaccid nor spastic is documented
•G81.01-G81.04 Flaccid hemiplegia with laterality: use when dominant/nondominant side is specified
•I69.051-I69.054 Hemiplegia following cerebrovascular disease: use the I69 sequelae codes when hemiplegia is specifically documented as a sequela of stroke