ICD10BillableValid for clinical use

ICD-10 Code G31.9: Degenerative disease of nervous system, unspecified

G31.9 is a billable ICD-10 diagnosis code used to classify Degenerative disease of nervous system, unspecified in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the nervous system (G00-G99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the nervous system (G00-G99).

When is it used?

  • May be used when a clinician documents degenerative disease of nervous system, unspecified in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
6Diseases of the nervous system (G00-G99)
block
G30-G32Other degenerative diseases of the nervous system
category
G31Other degenerative diseases of nervous system, not elsewhere classified
currentG31

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

NeurologistGeneral Physician

Coverage-related procedures and services

CPT 96105high
ASSESSMENT OF APHASIA (INCLUDES ASSESSMENT OF EXPRESSIVE AND RECEPTIVE SPEECH AND LANGUAGE FUNCTION, LANGUAGE COMPREHENSION, SPEECH PRODUCTION ABILITY, READING, SPELLING, WRITING, EG, BY BOSTON DIAGNOSTIC APHASIA EXAMINATION) WITH INTERPRETATION AND REPORT, PER HOUR
Source: CMS coverage guidance
CPT 78608high
BRAIN IMAGING, POSITRON EMISSION TOMOGRAPHY (PET); METABOLIC EVALUATION
Source: CMS coverage guidance
CPT 96113high
DEVELOPMENTAL TEST ADMINISTRATION (INCLUDING ASSESSMENT OF FINE AND/OR GROSS MOTOR, LANGUAGE, COGNITIVE LEVEL, SOCIAL, MEMORY AND/OR EXECUTIVE FUNCTIONS BY STANDARDIZED DEVELOPMENTAL INSTRUMENTS WHEN PERFORMED), BY PHYSICIAN OR OTHER QUALIFIED HEALTH CARE PROFESSIONAL, WITH INTERPRETATION AND REPORT; EACH ADDITIONAL 30 MINUTES (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 96112high
DEVELOPMENTAL TEST ADMINISTRATION (INCLUDING ASSESSMENT OF FINE AND/OR GROSS MOTOR, LANGUAGE, COGNITIVE LEVEL, SOCIAL, MEMORY AND/OR EXECUTIVE FUNCTIONS BY STANDARDIZED DEVELOPMENTAL INSTRUMENTS WHEN PERFORMED), BY PHYSICIAN OR OTHER QUALIFIED HEALTH CARE PROFESSIONAL, WITH INTERPRETATION AND REPORT; FIRST HOUR
Source: CMS coverage guidance
HCPCS A9601high
FLORTAUCIPIR F 18 INJECTION, DIAGNOSTIC, 1 MILLICURIE
Source: CMS coverage guidance
HCPCS A9552high
FLUORODEOXYGLUCOSE F-18 FDG, DIAGNOSTIC, PER STUDY DOSE, UP TO 45 MILLICURIES
Source: CMS coverage guidance

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
G31.9

Common synonyms

Degenerative disease of nervous system, unspecifiedDegenerative disease of nervous system

Frequently asked questions

Code details

CodeG31.9
SystemICD10
Display nameDegenerative disease of nervous system, unspecified
ChapterDiseases of the nervous system (G00-G99)
BlockOther degenerative diseases of the nervous system

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Atrophy, atrophic(of)Degeneration, degenerativeDegeneration, degenerativeDegeneration, degenerativeDegeneration, degenerativeHemiatrophy

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.