Is ICD-10-CM code G31 billable?

No, G31 (Other degenerative diseases of nervous system, not elsewhere classified) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code G31 belong to?

G31 belongs to Chapter 6 of the ICD-10-CM tabular list: G00–G99 (Diseases of the Nervous System).

G31Not billable, use a more specific code below

Other degenerative diseases of nervous system, not elsewhere classified

In Other degenerative diseases of the nervous system (G30-G32), chapter 6: Diseases of the Nervous System

14 billable codes under G31: 2 are a CC; 7 map to HCC 127 (Dementia, Mild or Unspecified), HCC 200 (Friedreich and Other Hereditary Ataxias; Huntington Disease).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Excludes2: not included here, code separately if applicable

Reye's syndrome (G93.7)

Use additional code: add a second code for this, listed after this one

code, if applicable, for codes G31.0-G31.83, G31.85-G31.9, to identify:
dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
mild neurocognitive disorder due to known physiological condition (F06.7-)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers default dominant or nondominant side for hemiplegia and monoplegia, and use and sequencing of G89 pain codes, including postoperative, chronic, and neoplasm-related pain.

Dominant/nondominant side (page 45)
Pain - Category G89 (page 45)

Read Section I.C.6 (page 45)

All codes under G31

G31 can't be used on a claim. Pick a billable code below; grey headings group them.

G31 MS-DRGs

As the principal diagnosis, all 14 billable codes under G31 group to MS-DRG 056 or 057 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Degenerative Nerve Diseases

Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses. Sometimes the cause is unknown.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.