Direct answer: Most established epilepsy diagnoses are reported from ICD-10-CM category G40. For example, G40.909 means epilepsy, unspecified, not intractable, without status epilepticus. G40.919 means epilepsy, unspecified, intractable, without status epilepticus.
The correct epilepsy code depends on the provider’s documentation of the epilepsy or seizure type, intractability, and whether status epilepticus is present. A coder should use the most specific code supported by the medical record and should not select a diagnosis from a short code description alone.
Last reviewed: October 2026. ICD-10-CM codes, payer policies, and claim requirements can change. Verify the current code set and the applicable payer’s instructions before submitting a claim.
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What Does the G40 ICD-10-CM Category Cover?
ICD-10-CM category G40 covers epilepsy and recurrent seizures. The available codes distinguish among different epilepsy types and syndromes. Many codes also identify whether the condition is intractable and whether status epilepticus is present.
The medical record should support every part of the selected code. Depending on the patient’s diagnosis, relevant documentation may include:
- The epilepsy or seizure type
- The diagnosed epilepsy syndrome, when known
- Whether the condition is intractable or refractory
- Whether status epilepticus is present
- The provider’s assessment and treatment plan
- Diagnostic findings relevant to the documented condition
Do not default to an unspecified code when the provider has documented enough detail to select a more specific code. When the record is unclear, follow the organization’s query process rather than assuming missing clinical details.
Common ICD-10-CM Codes for Unspecified Epilepsy
The following codes are common examples from the G40.9 family. They should be used only when the documentation supports unspecified epilepsy and the stated combination of intractability and status epilepticus.
| ICD-10-CM code | Description |
|---|---|
| G40.909 | Epilepsy, unspecified, not intractable, without status epilepticus |
| G40.919 | Epilepsy, unspecified, intractable, without status epilepticus |
| G40.901 | Epilepsy, unspecified, not intractable, with status epilepticus |
| G40.911 | Epilepsy, unspecified, intractable, with status epilepticus |
These four examples do not represent every epilepsy diagnosis. The G40 category also contains codes for focal epilepsy, generalized epilepsy, absence epileptic syndromes, juvenile myoclonic epilepsy, epileptic spasms, Dravet syndrome, and other documented conditions.
G40.909 Versus G40.919
G40.909 and G40.919 both describe unspecified epilepsy without status epilepticus. The difference is intractability:
- G40.909 is used when unspecified epilepsy is documented as not intractable and status epilepticus is not present.
- G40.919 is used when unspecified epilepsy is documented as intractable and status epilepticus is not present.
The coder should not infer intractability simply because the patient takes multiple medications, has had repeat visits, or has experienced another seizure. The diagnosis should be supported by the provider’s documentation and the applicable ICD-10-CM instructions.
The ICD-10-CM tabular information recognizes terms such as refractory, pharmacoresistant, treatment resistant, and poorly controlled as equivalent to intractable in the appropriate documented context. Always verify the current-year tabular instructions before assigning the final code.
Epilepsy Versus an Unspecified Seizure
Epilepsy and a seizure symptom are not automatically coded the same way. Category G40 is used for documented epilepsy and recurrent seizure diagnoses that fall within that category. R56.9 describes unspecified convulsions and may be relevant when the record documents a seizure or convulsion without an established epilepsy diagnosis.
Code selection must follow the provider’s documented diagnosis. A coder should not convert a single seizure, seizure-like event, or unspecified convulsion into epilepsy without clinical documentation supporting that diagnosis.
When the record contains conflicting or incomplete terminology, obtain clarification through the practice’s approved documentation-query process.
How Status Epilepticus Affects Code Selection
Many epilepsy code families distinguish between diagnoses with status epilepticus and diagnoses without status epilepticus. Status epilepticus should not be assumed merely because a seizure was prolonged, severe, or treated in an emergency setting.
The provider should clearly document whether status epilepticus is present. The coder can then select the code that represents the documented epilepsy type, intractability, and status combination.
For unspecified epilepsy, the common combinations include:
- Not intractable, without status epilepticus: G40.909
- Intractable, without status epilepticus: G40.919
- Not intractable, with status epilepticus: G40.901
- Intractable, with status epilepticus: G40.911
Epilepsy Coding Documentation Checklist
Before assigning an epilepsy diagnosis code, review whether the documentation answers the following questions:
- Is epilepsy clearly diagnosed? Distinguish an established epilepsy diagnosis from an isolated seizure, convulsion, or event still under evaluation.
- What type of epilepsy is documented? Look for focal, generalized, absence, juvenile myoclonic, or another named syndrome.
- Is the condition intractable? Use the provider’s documented terminology and applicable coding instructions.
- Is status epilepticus present? Do not infer this condition from treatment intensity alone.
- Does the code match the full documentation? Verify every character and descriptor in the current ICD-10-CM code set.
- Are other documented conditions relevant? Review the complete encounter rather than coding from one isolated sentence.
A Practical Epilepsy Code-Selection Process
A structured review can reduce unsupported or inconsistent code selection:
- Read the provider’s assessment and plan.
- Identify the documented epilepsy or seizure diagnosis.
- Confirm the epilepsy type or syndrome when specified.
- Determine whether intractability is documented.
- Determine whether status epilepticus is documented.
- Consult the current ICD-10-CM Alphabetic Index.
- Verify the tentative code in the current Tabular List.
- Review applicable inclusion notes, exclusion notes, and additional-code instructions.
- Confirm that the claim reflects the documentation for that date of service.
The Alphabetic Index is a starting point. Final code selection should be confirmed in the Tabular List.
CPT Coding for Epilepsy-Related Services
There is no single CPT code for epilepsy. ICD-10-CM codes report the diagnosis, while CPT codes report the professional or diagnostic service performed.
Depending on the encounter and documented service, epilepsy-related CPT reporting may involve:
- Office or other evaluation and management services
- Routine electroencephalography
- Extended, ambulatory, or video EEG monitoring
- Interpretation and reporting services
- Neuroimaging or other diagnostic testing
- Device-related services when medically appropriate
- Procedures performed as part of the documented treatment plan
The CPT code must match the service that was actually ordered, performed, documented, and reported by the appropriate provider. Time, technical components, professional components, place of service, payer policy, and bundling rules may affect claim reporting.
Use the current CPT code set and applicable payer guidance when reporting EEG or other epilepsy-related procedures. CMS also publishes Medicare billing guidance for certain electroencephalography services.
Common Epilepsy Coding Problems
Using G40.909 When a Specific Epilepsy Type Is Documented
G40.909 may be appropriate when the record supports unspecified epilepsy, not intractable, without status epilepticus. It should not replace a more specific diagnosis that is clearly documented and available in the current code set.
Assuming Intractability
A complicated medication history does not automatically establish intractable epilepsy. Assign the intractability element when it is supported by the provider’s documentation and current coding instructions.
Confusing a Seizure Symptom With Epilepsy
A seizure, convulsion, or seizure-like event does not always establish an epilepsy diagnosis. Follow the documented diagnosis for the encounter and query the provider when required.
Assuming Status Epilepticus
Do not assign a “with status epilepticus” code unless the condition is documented. Emergency treatment or a lengthy seizure description alone should not replace the provider’s diagnosis.
Choosing a Procedure Code From the Diagnosis
The epilepsy diagnosis does not determine which CPT service was performed. Review the order, procedure documentation, duration, monitoring method, interpretation, and payer requirements.
Failing to Verify the Current Code Set
Code descriptions and instructions may change between fiscal years. Check the code set applicable to the date of service.
Claim Review Before Submission
Before submitting an epilepsy-related claim, confirm that:
- The patient and insurance information is complete
- The diagnosis code matches the provider’s documentation
- The selected code reflects the documented epilepsy type
- Intractability is reported only when supported
- Status epilepticus is reported only when documented
- The procedure code matches the service performed
- Required professional or technical component reporting is correct
- The place of service is accurate
- The claim follows applicable payer and authorization requirements
A denial does not necessarily mean the diagnosis code is wrong. The practice should review the payer’s response, submitted claim, medical record, authorization information, and applicable policy before correcting or appealing the claim.
Official Epilepsy Coding Resources
- CMS FY 2026 ICD-10-CM epilepsy and seizure code reference
- CDC ICD-10-CM files, guidelines, and resources
- CMS billing and coding guidance for special electroencephalography
Official code sets and payer instructions should take priority over summaries, search snippets, and third-party code descriptions.
Support for Neurology Billing Workflows
Epilepsy claims often require careful coordination among clinical documentation, diagnosis coding, procedure reporting, authorization requirements, and payer follow-up. A consistent review process helps practices identify missing information before submission and understand the cause of rejected or denied claims.
Learn more about our neurology billing support, medical billing and coding services, and denial management services.
Need help reviewing your billing workflow? Contact Med Billing & Transcription to discuss your practice’s administrative support needs.
