G83.9
BillableParalytic syndrome, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G83.9 an HCC code?
Yes. G83.9 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 G83.9
For G83.9 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 G83.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G83.9 is the ICD-10-CM diagnosis code for paralytic syndrome, unspecified. Paralysis or weakness of muscles when the specific type or cause is not documented or identified. G83.9 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, G83.9 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, G83.9 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.
This is a last-resort code; query the provider if more specific information about the paralysis type is available. Because G83.9 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 G83.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a last-resort code; query the provider if more specific information about the paralysis type is available
- •Avoid using this code if documentation supports a more specific paralytic syndrome diagnosis
Clinical Significance
Unspecified paralytic syndrome is the least specific code in the paralytic syndromes section, indicating documentation merely states the patient has some form of paralysis without characterizing the pattern, distribution, or cause. This code should be a last resort and represents a significant documentation improvement opportunity. Even basic clinical examination can typically identify the pattern of paralysis sufficiently to assign a more specific code.
Documentation Requirements
- ✓Documentation of paralysis or paralytic syndrome
- ✓Clinical evidence supporting the diagnosis
- ✓Any available information about distribution, etiology, or pattern
- ✓Functional impact
- ✓Active management plan