G93.7
BillableReye's syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G93.7 an HCC code?
Yes. G93.7 maps to Dementia, Mild or Unspecified under the CMS-HCC V28 risk adjustment model.
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 G93.7
For G93.7 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 G93.7 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G93.7 is the ICD-10-CM diagnosis code for reye's syndrome. A rare but serious condition that causes brain and liver inflammation, typically occurring in children after a viral illness and characterized by vomiting, confusion, and seizures. G93.7 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering other disorders of the nervous system (g89-g99).
Under the CMS-HCC V28 risk adjustment model, G93.7 maps to Dementia, Mild or Unspecified (HCC 127) with a community, non-dual, aged base RAF weight of 0.464. G93.7 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. 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.
Always code the associated viral infection separately if documented. Because G93.7 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 G93.7 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Always code the associated viral infection separately if documented
- •This is a reportable condition in many jurisdictions; verify reporting requirements
Clinical Significance
Reye's syndrome is a rare but serious condition primarily affecting children and teenagers, characterized by acute non-inflammatory encephalopathy and fatty liver degeneration, often following viral illness with aspirin use. While now rare due to public health warnings about aspirin use in children, it remains a critical diagnosis with high mortality and significant long-term neurological morbidity in survivors. Documentation of this condition reflects historical or ongoing sequelae requiring monitoring.
Documentation Requirements
- ✓Clinical history of preceding viral illness (influenza, varicella) and aspirin or salicylate exposure
- ✓Laboratory findings including elevated ammonia, elevated transaminases, prolonged prothrombin time
- ✓Clinical staging of encephalopathy severity (Lovejoy staging I-V)
- ✓Imaging and/or liver biopsy findings when available
- ✓Long-term neurological outcome assessment for survivors
Use Additional Code
- code for adverse effect due to salicylates, if applicable (T39.0-, with sixth character 5)
Code First
- poisoning due to salicylates, if applicable (T39.0-, with sixth character 1-4)
Commonly Confused Codes
- •G93.41 — Metabolic encephalopathy: broader category of metabolic causes of brain dysfunction
- •K72.00 — Acute and subacute hepatic failure without coma: liver failure without the encephalopathy component specific to Reye's
- •G93.1 — Anoxic brain damage: different mechanism (oxygen deprivation vs metabolic/toxic encephalopathy)
- •E80.4 — Gilbert syndrome: benign liver condition, not the severe hepatic fatty degeneration of Reye's