G43.909
BillableMigraine, unspecified, not intractable, without status migrainosus
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G43.909 an HCC code?
No. G43.909 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
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 G43.909
For G43.909 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 G43.909 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G43.909 is the ICD-10-CM diagnosis code for migraine, unspecified, not intractable, without status migrainosus. A migraine headache of unspecified type that can be managed with treatment and does not have prolonged symptoms. G43.909 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering episodic and paroxysmal disorders (g40-g47).
G43.909 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
Maps to RxHCC 166 (Severe Head Injury) with a RAF weight of 0.000 in the prescription drug model. No mapping to CMS-HCC V28 or V24 payment models. While this code captures pharmacy risk equivalently to specific migraine codes, using a more specific code is always preferred for clinical accuracy and data quality. No hierarchies apply.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G43.909 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a default code for migraines when the specific type is not documented or cannot be classified
- •Ensure status migrainosus is not present; if it is, use G43.901 instead
Clinical Significance
Unspecified migraine codes are used when the provider documents migraine but does not specify the subtype (with/without aura, hemiplegic, chronic, etc.). While these codes are valid, they represent a missed opportunity for specificity and should prompt coders to query the provider for additional detail. Unspecified codes still map to RxHCC 166 and capture the pharmacy risk associated with migraine treatment.
Documentation Requirements
- ✓Provider documentation of migraine diagnosis (even without subtype specification)
- ✓Treatment response documented, or default to not intractable if not specified
- ✓Episode duration if available
- ✓Query opportunity: check for aura symptoms, frequency pattern, or specific variant that would support a more specific code
- ✓Migraine features present (headache with at least some typical migraine characteristics)
- ✓Current treatment plan