G83.23
BillableMonoplegia of upper limb affecting right nondominant side
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G83.23 an HCC code?
Yes. G83.23 maps to Monoplegia, Other Paralytic Syndromes under the CMS-HCC V28 risk adjustment model (and Monoplegia, Other Paralytic Syndromes 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 G83.23
For G83.23 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 G83.23 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G83.23 is the ICD-10-CM diagnosis code for monoplegia of upper limb affecting right nondominant side. Weakness or paralysis affecting only the right arm in a person whose right side is not their dominant side. G83.23 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, G83.23 maps to Monoplegia, Other Paralytic Syndromes (HCC 254) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, G83.23 mapped to the same category but with a base RAF weight of 0.304 — 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.
Ensure the medical record clearly documents that the patient is left-dominant before assigning this nondominant code. Because G83.23 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 G83.23 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure the medical record clearly documents that the patient is left-dominant before assigning this nondominant code
- •Consider the impact on activities of daily living when the nondominant arm is affected
Clinical Significance
Monoplegia of the upper limb affecting the right nondominant side occurs in left-handed individuals who lose function in their right (nondominant) arm. While less functionally devastating than dominant arm involvement, this still impacts bilateral tasks, carrying, and overall upper body function. The nondominant designation implies the patient retains use of their dominant left hand for most fine motor activities.
Documentation Requirements
- ✓Documentation of monoplegia isolated to the right upper extremity
- ✓Patient confirmed as left-hand dominant (right is nondominant)
- ✓Underlying etiology documented
- ✓Motor strength findings
- ✓Functional impact assessment
- ✓Active treatment plan
Commonly Confused Codes
- •G83.21 Monoplegia of upper limb, right dominant — right arm in a right-handed person
- •G83.24 Monoplegia of upper limb, left nondominant — different arm affected
- •G81.03 Flaccid hemiplegia, right nondominant — includes lower extremity on right side
- •G83.20 Monoplegia of upper limb, unspecified — when laterality unknown