2027 ICD-10-CM Diagnosis Code G93.40Encephalopathy, unspecified

ICD-10-CM Codes›G00–G99›G89-G99›G93

ICD-10-CM G93.40
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G93.40 is a billable ICD-10-CM diagnosis code for encephalopathy, unspecified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 70 through 72, 974 through 976. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 10 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (neither hereditary nor degenerative).

Code Identity

ICD-10-CM Code
G93.40
Billable Status
Yes — Valid for Submission
Code Describes
Encephalopathy, unspecified
Short Description
Encephalopathy, unspecified
Same as the full description in the CMS dataset.
Parent Code
G93.4
Other and unspecified encephalopathy

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG89-G99Other disorders of the nervous system
CategoryG93Other disorders of brain
This CodeG93.40Encephalopathy, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • CNTNAP2-related developmental and epileptic encephalopathy
  • Congenital axonal neuropathy with encephalopathy
  • Encephalopathy due to and following cardiopulmonary bypass
  • Encephalopathy due to COVID-19
  • Encephalopathy due to prosaposin deficiency
  • Encephalopathy with AIDS
  • Encephalopathy, intracerebral calcification, retinal degeneration syndrome
  • Epileptic encephalopathy with global cerebral demyelination
  • Hypomyelination of central nervous system structure
  • Ischemic encephalopathy
  • RAVINE syndrome
  • Recurrent encephalopathy
  • Renal tubulopathy with encephalopathy and liver failure syndrome
  • SCN8A developmental and epileptic encephalopathy
  • Static encephalopathy

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G93.40: its own notes plus those printed at G93.4 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

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.

From G93.4 Other and unspecified encephalopathy applies to 7 codes
  • alcoholic encephalopathy (G31.2)
  • encephalopathy in diseases classified elsewhere (G94)
  • hypertensive encephalopathy (I67.4)
  • toxic (metabolic) encephalopathy (G92.8)
From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 codes
  • 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)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G93.40, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming G93.40: they are not reported together with it, unless the two conditions are unrelated.

  • G04 Encephalitis, myelitis and encephalomyelitis
    encephalopathy NOS (G93.40)

Code Also 1

These codes say G93.40 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • F78.A1 SYNGAP1-related intellectual disability
    encephalopathy (G93.4-) names G93.4-, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G93.40 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
348.30 Encephalopathy NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G93.40Overview

What is the ICD-10 code for encephalopathy, unspecified?

The ICD-10-CM code for encephalopathy, unspecified is G93.40 (sometimes written as G9340). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G93.40 (Other and unspecified encephalopathy) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report encephalopathy, unspecified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does G93.40 group to?

When encephalopathy, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 974, 976, 72, 975, 70, 71, with relative weights from 0.7344 to 3.0488 depending on complications. Higher weights mean higher Medicare reimbursement.

Is G93.40 a CC or MCC?

CMS lists G93.40 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 10 closely related codes in its exclusion list.

What is the ICD-9 equivalent of G93.40?

Under the General Equivalence Mappings, encephalopathy, unspecified converts to ICD-9-CM 348.30 (encephalopathy NOS). The mapping is a direct match.