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G40.A09 ICD-10-CM Code: Absence epileptic syndrome, not intractable, without status epilepticus

G40.A09 maps to CMS-HCC V28 201. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupG40.A09

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

G40.A09

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

Absence epileptic syndrome, not intractable, without status epilepticus

Absence epilepsy (characterized by brief lapses in consciousness) that responds to medication, without current status epilepticus.

Buddy the Bee presenting code insight

Buddy Insight

Absence epileptic syndrome, controlled and without status epilepticus, is a common childhood epilepsy characterized by brief staring spells lasting 5-30 seconds with abrupt onset and offset.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 201

Coefficient HCC 201: 0.245 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 120

Code-level coefficient reference

ESRD/PACE

HCC 79

Code-level coefficient reference

RXHCC

HCC 164

Code-level coefficient reference

Code Book Path

Official
G40.AAbsence epileptic syndromeG40.A0Absence epileptic syndrome, not intractableG40.A09Absence epileptic syndrome, not intractable, without status epilepticus

Inclusion Terms

Official
  • Childhood absence epilepsy [pyknolepsy]Inherited from G40.A
  • Juvenile absence epilepsyInherited from G40.A
  • Absence epileptic syndrome, NOSInherited from G40.A

Excludes 2

Official
  • certain conditions originating in the perinatal period (P04-P96)Inherited from G00-G99, G40
  • certain infectious and parasitic diseases (A00-B99)Inherited from G00-G99, G40
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from G00-G99, G40
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from G00-G99, G40
  • endocrine, nutritional and metabolic diseases (E00-E88)Inherited from G00-G99, G40
  • injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from G00-G99, G40
  • neoplasms (C00-D49)Inherited from G00-G99, G40
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from G00-G99, G40
  • hippocampal sclerosis (G93.81)Inherited from G00-G99, G40
  • mesial temporal sclerosis (G93.81)Inherited from G00-G99, G40
  • temporal sclerosis (G93.81)Inherited from G00-G99, G40
  • Todd's paralysis (G83.84)Inherited from G00-G99, G40

Related Codes

Official
G40.A01Absence epileptic syndrome, not intractable, with status epilepticus

Includes

Official

No Includes notes are included in this display for G40.A09. Check the code and parent instructions in the Code Book.

Excludes 1

Official
  • conversion disorder with seizures (F44.5)Inherited from G40
  • convulsions NOS (R56.9)Inherited from G40
  • post traumatic seizures (R56.1)Inherited from G40
  • seizure (convulsive) NOS (R56.9)Inherited from G40
  • seizure of newborn (P90)Inherited from G40

Code First

Official

No Code First sequencing instructions are included in this display for G40.A09. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for G40.A09. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for G40.A09. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Confirmed absence epilepsy diagnosis
EEG findings showing generalized spike-and-wave discharges
Seizure control documentation (not intractable)
Absence of status epilepticus

MEAT Support

HCC Buddy guidance
Confirmed absence epilepsy diagnosis
EEG findings showing generalized spike-and-wave discharges
Seizure control documentation (not intractable)
Absence of status epilepticus

Audit Caution

HCC Buddy guidance
Confusing absence seizures with daydreaming or inattention in children
Using this code for focal seizures with impaired awareness that may look like absences clinically
Not updating coding when childhood absence epilepsy remits and the patient no longer has seizures
Failing to distinguish typical absence epilepsy from juvenile absence epilepsy (different age of onset and prognosis)

Common Mistakes

HCC Buddy guidance
G40.A01 — Absence epilepsy WITH status epilepticus
G40.A19 — Absence epilepsy, INTRACTABLE, without status epilepticus
G40.B09 — Juvenile myoclonic epilepsy; may coexist with absence seizures but is a different syndrome
G40.909 — Unspecified epilepsy; less specific when absence type is documented

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is G40.A09 an HCC code?

Yes. G40.A09 (Absence epileptic syndrome, not intractable, without status epilepticus) maps to HCC 201, Seizure Disorders and Convulsions under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.245. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: G40.A09 is billable and maps to V28 HCC 201, Seizure Disorders and Convulsions. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
G40.A09
Description
Absence epileptic syndrome, not intractable, without status epilepticus
HCC (V28)
HCC 201 — Seizure Disorders and Convulsions
RAF reference coefficient
0.245
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 201, Seizure Disorders and Convulsions
0.245
ESRDHCC 79, Seizure Disorders and Convulsions
Not separately weighted
RxHCCHCC 164, Epilepsy and Other Seizure Disorders, Except Intractable Epilepsy
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work G40.A09 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for G40.A09

For G40.A09, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • 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

Coder workflow notes

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What This Code Means

G40.A09 is the ICD-10-CM diagnosis code for absence epileptic syndrome, not intractable, without status epilepticus. Absence epilepsy (characterized by brief lapses in consciousness) that responds to medication, without current status epilepticus. G40.A09 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).

Under the CMS-HCC V28 risk adjustment model, G40.A09 maps to Seizure Disorders and Convulsions (HCC 201) with a source-labeled community, non-dual, aged reference coefficient of 0.245. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Absence epilepsy is more common in children and typically has a good prognosis with medication. For G40.A09, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for G40.A09 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Absence epilepsy is more common in children and typically has a good prognosis with medication
  • •Document the frequency and duration of absence episodes for clinical clarity

Clinical Significance

Absence epileptic syndrome, controlled and without status epilepticus, is a common childhood epilepsy characterized by brief staring spells lasting 5-30 seconds with abrupt onset and offset. This syndrome has a generally favorable prognosis with many children outgrowing seizures by adolescence. Proper identification is important for school accommodations and driving restrictions.

Documentation Requirements

  • ✓Confirmed absence epilepsy diagnosis
  • ✓EEG findings showing generalized spike-and-wave discharges
  • ✓Seizure control documentation (not intractable)
  • ✓Absence of status epilepticus
  • ✓Seizure frequency and school impact
  • ✓Current medication regimen and compliance

Commonly Confused Codes

  • •G40.A01: Absence epilepsy WITH status epilepticus
  • •G40.A19: Absence epilepsy, INTRACTABLE, without status epilepticus
  • •G40.B09: Juvenile myoclonic epilepsy; may coexist with absence seizures but is a different syndrome
  • •G40.909: Unspecified epilepsy; less specific when absence type is documented
  • •R55: Syncope; may mimic absence seizures clinically

Child Codes

G40.A01Absence epileptic syndrome, not intractable, with status epilepticus
HCC 201
G40.A09Absence epileptic syndrome, not intractable, without status epilepticus
HCC 201

Code Hierarchy

└G40Epilepsy and recurrent seizures└G40.AAbsence epileptic syndrome└G40.A0Absence epileptic syndrome, not intractable└G40.A09Absence epileptic syndrome, not intractable, without status epilepticus
└G40.A09Absence epileptic syndrome, not intractable, without status epilepticus

Also searched as

  • G40 A09
  • G40A09

For G40.A09, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

G40.A09 maps to CMS-HCC V28 category 201, Seizure Disorders and Convulsions. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for G40.A09. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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