G40.309 — Generalized idiopathic epilepsy and epileptic syndromes, not intractable, without status epilepticus
Is G40.309 billable?
Yes — G40.309 is billable for FY2027. G40.309 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. G40.309 may be submitted for encounters from October 1, 2026 through September 30, 2027.
G40.309 at a glance
| Code | G40.309 |
|---|---|
| Description | Generalized idiopathic epilepsy and epileptic syndromes, not intractable, without status epilepticus |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does G40.309 group to?
G40.309 sits in MDC 01 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 023Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulatorsurgical
How is G40.309 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to G40.309. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Epilepsy, epileptic, epilepsia › generalized › idiopathic (attack) (cerebral) (convulsion) (fit) (seizure)
- Epilepsy, epileptic, epilepsia › generalized › idiopathic › not intractable (attack) (cerebral) (convulsion) (fit) (seizure)
- Epilepsy, epileptic, epilepsia › syndromes › generalized › idiopathic (attack) (cerebral) (convulsion) (fit) (seizure)
- Epilepsy, epileptic, epilepsia › generalized › idiopathic › not intractable › without status epilepticus (attack) (cerebral) (convulsion) (fit) (seizure)
- Epilepsy, epileptic, epilepsia › syndromes › generalized › idiopathic › not intractable (attack) (cerebral) (convulsion) (fit) (seizure)
- Epilepsy, epileptic, epilepsia › syndromes › generalized › idiopathic › not intractable › without status epilepticus (attack) (cerebral) (convulsion) (fit) (seizure)
Inclusion terms
Alternative wording in documentation that is classified to G40.309.
- Generalized idiopathic epilepsy and epileptic syndromes NOS
Excludes1 — never code together — inherited from G40
The conditions below can never be reported together with G40.309 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from Chapter 6
The conditions below are not part of G40.309, but a patient may have both at the same time. When documentation supports it, G40.309 and the excluded code may both be reported.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from G40
The conditions below are not part of G40.309, but a patient may have both at the same time. When documentation supports it, G40.309 and the excluded code may both be reported.
Code also — inherited from G40.3
Two codes may be needed to describe the condition fully. Whether G40.309 is sequenced first depends on the reason for the encounter.
- MERRF syndrome, if applicable (E88.42)
How long has G40.309 existed?
G40.309 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.