ICD-10 G40.909
Billable / Specific HCC v28: 79Epilepsy, unspecified, not intractable, without status epilepticus
About ICD-10-CM G40.909
ICD-10-CM code G40.909 represents Epilepsy, unspecified, not intractable, without status epilepticus. This is a billable/specific code in the Nervous System chapter (block G40). The 2026 edition of ICD-10-CM G40.909 became effective on October 1, 2025.
Coding Tips for G40.909
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
G40.909 is a CMS-HCC v28 risk-adjustment code (category 79). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under G40.909. Per CMS ICD-10-CM Tabular 2026.
- Epilepsy NOS
- Epileptic convulsions NOS
- Epileptic fits NOS
- Epileptic seizures NOS
- Recurrent seizures NOS
- Seizure disorder NOS
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Medicare LCD Coverage for G40.909
Local Coverage Determinations (LCDs) from CMS MACs that list G40.909 as a covered diagnosis.
Showing top 10 of 408 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing G40.909.
2 Cigna
5 Medicare
CPT Codes Commonly Billed with G40.909
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 99205 New patient office visit — complex/high-risk: uncontrolled diabetes, heart failure, COPD exacerbation, cancer, MS, RA, CKD, CAD, recurrent depression, epilepsy, lupus, syncope, cognitive decline Primary Care
- 99215 Established patient — high complexity: HF exacerbation, COPD exacerbation, cancer management, MS, advanced CKD, uncontrolled diabetes, recurrent syncope, respiratory failure, liver cirrhosis Primary Care
- 70553 MRI brain with and without contrast — migraine, headache, encephalopathy, brain cancer, epilepsy, brain neoplasm, cognitive decline, MS, hydrocephalus, aphasia, numbness Radiology
- 70551 MRI brain without contrast — migraine, headache, encephalopathy, cognitive decline, MS, epilepsy, syncope, dizziness Radiology
- 95819 EEG awake and asleep — epilepsy, generalized seizures, absence seizures, focal seizures, seizure NOS, fasciculations, syncope, encephalopathy, cognitive decline, aphasia, migraine, headache, insomnia Neurology
- 95816 EEG awake only — epilepsy, seizures, encephalopathy, cognitive decline, syncope Neurology
- 95711 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95714 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95726 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
- 95709 CMS LCD: Billing and Coding: EEG � Ambulatory Monitoring CMS LCD
Convert G40.909 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| G40.909 | 34590 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To G40.909
Other codes in section G40-G47 (Episodic and paroxysmal disorders).
ICD-10 G40.909, Billing FAQ
Is ICD-10 code G40.909 billable? +
Yes, G40.909 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to G40.909? +
ICD-10 G40.909 includes: Epilepsy NOS; Epileptic convulsions NOS; Epileptic fits NOS, and 3 more clinical synonyms.
Does G40.909 affect Medicare Advantage HCC risk adjustment? +
Yes. G40.909 maps to CMS-HCC v28 category 79. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with G40.909? +
Procedures frequently paired with G40.909 include: 99205, 99215, 70553, 70551, 95819.
What ICD-9 codes does G40.909 map to? +
Per CMS GEMs, G40.909 maps to ICD-9 codes: 34590. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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