What is ICD-10 code G43.919?

G43.919 is the ICD-10-CM diagnosis code for Migraine, unspecified, intractable, without status migrainosus. A migraine headache of unspecified type that does not respond well to treatment and does not have prolonged symptoms. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G43.919 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G43.919 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. G43.919 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. G43.919 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 G43.919?

G43.919 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards G43.919 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting G43.919?

Intractable status requires documentation of treatment failures and resistance to standard migraine therapies Confirm status migrainosus is absent; if present, additional coding may be needed

G43.919: Migraine, unspecified, intractable

ICD-10-CM Code View

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Code lookupG43.919Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)

G43.919

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

Migraine, unspecified, intractable, without status migrainosus

A migraine headache of unspecified type that does not respond well to treatment and does not have prolonged symptoms.

Buddy Insight

Unspecified migraine codes are used when the provider documents migraine but does not specify the subtype (with/without aura, hemiplegic, chronic, etc.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 166

Migraine

RAF 0.0

Code Trumping

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Code Book Path

Official

G43.9Migraine, unspecified

G43.91Migraine, unspecified, intractable

G43.919Migraine, unspecified, intractable, without status migrainosus

Inclusion Terms

Official

Migraine, unspecified, with refractory migraine

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G43.919 in this effective period.

Related Child Codes

Official

G43.911Migraine, unspecified, intractable, with status migrainosus

Includes

Official

ICD-10-CM does not list Includes notes for G43.919 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G43.919 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G43.919 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G43.919 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G43.919 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation of migraine diagnosis (even without subtype specification)

Intractability status if documented

Episode duration if available

Query opportunity: check for aura symptoms, frequency pattern, or specific variant that would support a more specific code

MEAT Support

HCC Buddy guidance

Provider documentation of migraine diagnosis (even without subtype specification)

Intractability status if documented

Episode duration if available

Query opportunity: check for aura symptoms, frequency pattern, or specific variant that would support a more specific code

Audit Caution

HCC Buddy guidance

Accepting unspecified migraine when the medical record contains enough detail to code a specific subtype

Not querying the provider when aura status, frequency, or variant type is documented elsewhere in the record

Defaulting to unspecified for all migraine encounters rather than reviewing for specificity

Using unspecified codes for conditions that clearly match hemiplegic, chronic, or other specific migraine subtypes

Common Mistakes

HCC Buddy guidance

G43.001-G43.019 (Migraine without aura) — use when provider documents absence of aura; more specific than unspecified

G43.101-G43.119 (Migraine with aura) — use when visual/sensory/speech aura is documented

G43.701-G43.719 (Chronic migraine without aura) — use when frequency >=15 days/month is documented

R51.9 (Headache, unspecified) — even more nonspecific; use migraine codes when migraine is diagnosed

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is G43.919 an HCC code?

No. G43.919 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 166, Migraine

0.000

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 G43.919

For G43.919to 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 G43.919 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

G43.919 is the ICD-10-CM diagnosis code for migraine, unspecified, intractable, without status migrainosus. A migraine headache of unspecified type that does not respond well to treatment and does not have prolonged symptoms. G43.919 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).

G43.919 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 G43.919 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Intractable status requires documentation of treatment failures and resistance to standard migraine therapies
•Confirm status migrainosus is absent; if present, additional coding may be needed

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)
✓Intractability status if documented
✓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

Commonly Confused Codes

•G43.001-G43.019 (Migraine without aura): use when provider documents absence of aura; more specific than unspecified
•G43.101-G43.119 (Migraine with aura): use when visual/sensory/speech aura is documented
•G43.701-G43.719 (Chronic migraine without aura): use when frequency >=15 days/month is documented
•R51.9 (Headache, unspecified): even more nonspecific; use migraine codes when migraine is diagnosed
•G44.1 (Vascular headache, NEC): different classification; migraine should be coded as migraine

Child Codes

G43.911Migraine, unspecified, intractable, with status migrainosus

G43.919Migraine, unspecified, intractable, without status migrainosus

Code Hierarchy

└G43Migraine └G43.9Migraine, unspecified └G43.91Migraine, unspecified, intractable └G43.919Migraine, unspecified, intractable, without status migrainosus

└G43.919Migraine, unspecified, intractable, without status migrainosus

G43.919 ICD-10-CM Code: Migraine, unspecified, intractable, without status migrainosus

HCC Buddy Code Card

G43.919

Is G43.919 an HCC code?

HCC Category Mapping

MEAT Criteria for G43.919

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What This Code Means

Coding Tips

Clinical Significance

Documentation Requirements

Commonly Confused Codes

Child Codes

Code Hierarchy

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