2027 ICD-10-CM Diagnosis Code G40.901Epilepsy, unspecified, not intractable, with status epilepticus
ICD-10-CM Codes›G00–G99›G40-G47›G40
- Billable — Valid for Submission
- Risk Adjusts — HCC 201
- Chronic Condition
G40.901 is a billable ICD-10-CM diagnosis code for epilepsy, unspecified, not intractable, with status epilepticus. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 23, 100 through 101. Coders also document this condition as idiopathic partial status epilepticus. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Epilepsy; convulsions.
For Medicare Advantage risk adjustment, G40.901 maps to CMS-HCC Category 201 (Seizure Disorders and Convulsions) under the V28 model, adding a risk factor of about 0.245 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
G40.901 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Idiopathic partial status epilepticus
- Status epilepticus
- Status epilepticus with prominent motor symptoms
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to G40.901: its own notes plus those printed at G40 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may 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)
Notes
General instructions on how these codes are used.
- the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name G40.901, its category, or a range that includes it.
Excludes1 4
These codes carry an Excludes1 note naming G40.901: they are not reported together with it, unless the two conditions are unrelated.
- R56.01 Complex febrile convulsionsstatus epilepticus (G40.901)
- G25.3 Myoclonusmyoclonic epilepsy (G40.-) names G40.-, which includes this code
- R56 Convulsions, not elsewhere classifiedepileptic convulsions and seizures (G40.-) names G40.-, which includes this code
- R56.1 Post traumatic seizurespost traumatic epilepsy (G40.-) names G40.-, which includes this code
Excludes2 2
These codes carry an Excludes2 note naming G40.901: its condition is not part of those codes, and both may be reported when the patient has both.
Code First 1
These codes say to code first a condition named in the note, and G40.901 is one of the conditions named.
Use Additional Code 2
These codes say to use an additional code from the note, and G40.901 is one of the codes named.
Code Also 10
These codes say G40.901 may also be needed to fully describe the condition. The note gives no sequencing direction.
- E20.810 Autosomal dominant hypocalcemiaseizure disorder (G40.-, R56.9) names G40.-, which includes this code
- F78.A1 SYNGAP1-related intellectual disabilityepilepsy and recurrent seizures (G40.-) names G40.-, which includes this code
- G04.8 Other encephalitis, myelitis and encephalomyelitisany associated seizure (G40.-, R56.9) names G40.-, which includes this code
- G40.5 Epileptic seizures related to external causesif applicable, associated epilepsy and recurrent seizures (G40.-) names G40.-, which includes this code
- G43.1 Migraine with auraany associated seizure (G40.-, R56.9) names G40.-, which includes this code
- G93.45 Developmental and epileptic encephalopathyepilepsy, by specific type (G40.-) names G40.-, which includes this code
- I67.850 Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathyepilepsy (G40.-) names G40.-, which includes this code
- Q87.85 MED13L syndromeepilepsy and recurrent seizures (G40.-) names G40.-, which includes this code
- QA0 Neurodevelopmental disorders related to specific genetic pathogenic variantsepilepsy, by specific type (G40.-) names G40.-, which includes this code
- Z15.1 Genetic susceptibility to epilepsy and neurodevelopmental disordersepilepsy, by specific type (G40.-) names G40.-, which includes this code
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Convulsions (idiopathic) See Also: Seizure(s); R56.9
with status epilepticus G40.901
with status epilepticus G40.901
Seizure (s) See Also: Convulsions; R56.9
Status (post) See Also: Presence (of);
epileptic, epilepticus See Also: Epilepsy, by type, with status epilepticus; G40.901
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Epilepsy
a disorder characterized by recurrent episodes of paroxysmal brain dysfunction due to a sudden, disorderly, and excessive neuronal discharge. epilepsy classification systems are generally based upon: (1) clinical features of the seizure episodes (e.g., motor seizure), (2) etiology (e.g., post-traumatic), (3) anatomic site of seizure origin (e.g., frontal lobe seizure), (4) tendency to spread to other structures in the brain, and (5) temporal patterns (e.g., nocturnal epilepsy). (from adams et al., principles of neurology, 6th ed, p313)
Patient EducationClinical
Epilepsy
Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert G40.901 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About G40.901Overview
What is the ICD-10 code for epilepsy, unspecified, not intractable, with status epilepticus?
The ICD-10-CM code for epilepsy, unspecified, not intractable, with status epilepticus is G40.901 (sometimes written as G40901). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is G40.901 (Epilepsy, unspecified, not intractable) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report epilepsy, unspecified, not intractable, with status epilepticus on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does G40.901 group to?
When epilepsy, unspecified, not intractable, with status epilepticus is the principal diagnosis on an inpatient stay, it groups to MS-DRG 100, 23, 101, with relative weights from 0.8952 to 5.7422 depending on complications. Higher weights mean higher Medicare reimbursement.
Can G40.901 be reported with F44.5?
Not as a rule. The Excludes1 note at G40, which applies to G40.901, lists "conversion disorder with seizures (F44.5)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of G40.901?
Under the General Equivalence Mappings, epilepsy, unspecified, not intractable, with status epilepticus converts to ICD-9-CM 345.90 (epilep NOS w/o intr epil). The mapping is approximate, so confirm the match fits the documentation.
What HCC is G40.901?
G40.901 (epilepsy, unspecified, not intractable, with status epilepticus) maps to CMS-HCC Category 201 (Seizure Disorders and Convulsions), commonly written as HCC 201, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 79 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 164.
Does G40.901 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, G40.901 adds a risk adjustment factor of about 0.245 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.131 to 0.245 depending on the payment segment). HCC 201 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 201 category page.
