What is ICD-10 code G43.A0?

G43.A0 is the ICD-10-CM diagnosis code for Cyclical vomiting, in migraine, not intractable. Repeated episodes of severe vomiting associated with migraines that can be managed with treatment. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G43.A0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G43.A0 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.A0 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.A0 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.A0?

G43.A0 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.A0 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.A0?

Cyclical vomiting must be documented as occurring in the context of migraine, not as a separate condition This code indicates the vomiting is responsive to migraine treatment

G43.A0: Cyclical vomiting, in migraine, not intractable — ICD-10

ICD-10-CM Code View

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Code lookupG43.A0Effective 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.A0

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

Cyclical vomiting, in migraine, not intractable

Repeated episodes of severe vomiting associated with migraines that can be managed with treatment.

Buddy Insight

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

G43Migraine

G43.ACyclical vomiting

G43.A0Cyclical vomiting, in migraine, not intractable

Inclusion Terms

Official

Cyclical vomiting, without refractory migraine

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G43.A0 in this effective period.

Related Child Codes

Official

G43.A1Cyclical vomiting, in migraine, intractable

Includes

Official

ICD-10-CM does not list Includes notes for G43.A0 in this effective period.

Excludes 1

Official

cyclical vomiting syndrome unrelated to migraine (R11.15)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G43.A0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G43.A0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G43.A0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Recurrent episodes of intense vomiting following a stereotypical pattern

Provider documentation linking cyclical vomiting to migraine pathophysiology

Episode frequency, duration, and symptom-free interval documentation

Exclusion of metabolic, gastrointestinal, or other causes of cyclical vomiting

MEAT Support

HCC Buddy guidance

Recurrent episodes of intense vomiting following a stereotypical pattern

Provider documentation linking cyclical vomiting to migraine pathophysiology

Episode frequency, duration, and symptom-free interval documentation

Exclusion of metabolic, gastrointestinal, or other causes of cyclical vomiting

Audit Caution

HCC Buddy guidance

Coding non-migraine cyclical vomiting syndrome with migraine codes — the migraine link must be established

Using generic vomiting codes (R11.x) when cyclical vomiting in migraine is diagnosed

Not distinguishing intractable from not intractable — intractable implies failed preventive therapy

Overlooking cannabinoid hyperemesis syndrome as a differential in patients with cannabis use history

Common Mistakes

HCC Buddy guidance

R11.10 (Vomiting, unspecified) — nonspecific; use G43.A when cyclical pattern linked to migraine is established

R11.15 (Cyclical vomiting syndrome, unrelated to migraine) — use when cyclical vomiting has no migraine association

G43.909 (Migraine, unspecified, without status migrainosus) — does not capture the cyclical vomiting variant

K31.89 (Other diseases of stomach and duodenum) — GI causes should be excluded before coding migraine-related CVS

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.A0 an HCC code?

No. G43.A0 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.A0

For G43.A0to 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.A0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

G43.A0 is the ICD-10-CM diagnosis code for cyclical vomiting, in migraine, not intractable. Repeated episodes of severe vomiting associated with migraines that can be managed with treatment. G43.A0 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.A0 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. The RxHCC mapping captures the pharmacy costs of migraine-variant management (antiemetics, triptans, preventive medications). No hierarchies apply.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G43.A0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Cyclical vomiting must be documented as occurring in the context of migraine, not as a separate condition
•This code indicates the vomiting is responsive to migraine treatment

Clinical Significance

Cyclical vomiting syndrome in the context of migraine is an episodic condition characterized by recurrent, stereotypical episodes of intense nausea and vomiting, often with headache and migraine features. This condition is recognized as a migraine variant and is distinct from other causes of cyclical vomiting such as metabolic disorders or cannabinoid hyperemesis syndrome. Accurate coding captures the migraine relationship which guides treatment with migraine-specific prophylaxis and abortive therapies.

Documentation Requirements

✓Recurrent episodes of intense vomiting following a stereotypical pattern
✓Provider documentation linking cyclical vomiting to migraine pathophysiology
✓Episode frequency, duration, and symptom-free interval documentation
✓Exclusion of metabolic, gastrointestinal, or other causes of cyclical vomiting
✓Associated migraine features (headache, photophobia, phonophobia) if present
✓Treatment response noted (not intractable = responsive to therapy)
✓Emergency department utilization pattern if applicable

Commonly Confused Codes

•R11.10 (Vomiting, unspecified): nonspecific; use G43.A when cyclical pattern linked to migraine is established
•R11.15 (Cyclical vomiting syndrome, unrelated to migraine): use when cyclical vomiting has no migraine association
•G43.909 (Migraine, unspecified, without status migrainosus): does not capture the cyclical vomiting variant
•K31.89 (Other diseases of stomach and duodenum): GI causes should be excluded before coding migraine-related CVS
•F50.89 (Other specified eating disorder): psychogenic vomiting is a different entity

Child Codes

G43.A0Cyclical vomiting, in migraine, not intractable

G43.A1Cyclical vomiting, in migraine, intractable

Code Hierarchy

└G43Migraine └G43.ACyclical vomiting └G43.A0Cyclical vomiting, in migraine, not intractable

└G43.A0Cyclical vomiting, in migraine, not intractable

G43.A0 ICD-10-CM Code: Cyclical vomiting, in migraine, not intractable

HCC Buddy Code Card

G43.A0

Is G43.A0 an HCC code?

HCC Category Mapping

MEAT Criteria for G43.A0

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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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