ICD10BillableValid for clinical use
ICD-10 Code G31.84: Mild cognitive impairment of uncertain or unknown etiology
G31.84 is a billable ICD-10 diagnosis code used to classify Mild cognitive impairment of uncertain or unknown etiology 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 mild cognitive impairment of uncertain or unknown etiology 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
category
G31.8Other specified degenerative diseases of nervous system
currentG31.8
Official coding notes
Inclusion terms
- Mild cognitive disorder NOS
- Mild neurocognitive disorder of uncertain or unknown etiology
Applicable to
- code to identify presence of:
- alcohol abuse and dependence (F10.-)
- exposure to environmental tobacco smoke (Z77.22)
- history of tobacco dependence (Z87.891)
- hypertension (I10-I1A)
- occupational exposure to environmental tobacco smoke (Z57.31)
- tobacco dependence (F17.-)
- tobacco use (Z72.0)
Excludes1 (do not code together)
- age related cognitive decline (R41.81)
- altered mental status (R41.82)
- cerebral degeneration (G31.9)
- cerebrovascular diseases (I60-I69)
- change in mental status (R41.82)
- cognitive deficits following (sequelae of) cerebral hemorrhage or infarction (I69.01-, I69.11-, I69.21-, I69.31-, I69.81-, I69.91-)
- cognitive impairment due to intracranial or head injury (S06.-)
- dementia (F01.-, F02.-, F03.-)
- mild neurocognitive disorder due to a known physiological condition (F06.7-)
- neurologic neglect syndrome (R41.4)
- personality change, nonpsychotic (F68.8)
Use additional code
- code to identify presence of:
- alcohol abuse and dependence (F10.-)
- exposure to environmental tobacco smoke (Z77.22)
- history of tobacco dependence (Z87.891)
- hypertension (I10-I1A)
- occupational exposure to environmental tobacco smoke (Z57.31)
- tobacco dependence (F17.-)
- tobacco use (Z72.0)
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
Related codes
G31.80Leukodystrophy, unspecifiedcodeG31.81Alpers diseasecodeG31.82Leigh's diseasecodeG31.83Neurocognitive disorder with Lewy bodiescodeG31.85Corticobasal degenerationcodeG31.86Alexander diseasecodeG31.87Primary progressive apraxia of speechcodeG31.89Other specified degenerative diseases of nervous systemcode
Sibling codes
G31.80Leukodystrophy, unspecifiedbillableG31.81Alpers diseasebillableG31.82Leigh's diseasebillableG31.83Neurocognitive disorder with Lewy bodiesbillableG31.85Corticobasal degenerationbillableG31.86Alexander diseasebillableG31.87Primary progressive apraxia of speechbillableG31.89Other specified degenerative diseases of nervous systembillable
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
HCPCS G0451high
DEVELOPMENT TESTING, WITH INTERPRETATION AND REPORT, PER STANDARDIZED INSTRUMENT FORM
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
CPT 96133high
NEUROPSYCHOLOGICAL TESTING EVALUATION SERVICES BY PHYSICIAN OR OTHER QUALIFIED HEALTH CARE PROFESSIONAL, INCLUDING INTEGRATION OF PATIENT DATA, INTERPRETATION OF STANDARDIZED TEST RESULTS AND CLINICAL DATA, CLINICAL DECISION MAKING, TREATMENT PLANNING AND REPORT, AND INTERACTIVE FEEDBACK TO THE PATIENT, FAMILY MEMBER(S) OR CAREGIVER(S), WHEN PERFORMED; EACH ADDITIONAL HOUR (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 96132high
NEUROPSYCHOLOGICAL TESTING EVALUATION SERVICES BY PHYSICIAN OR OTHER QUALIFIED HEALTH CARE PROFESSIONAL, INCLUDING INTEGRATION OF PATIENT DATA, INTERPRETATION OF STANDARDIZED TEST RESULTS AND CLINICAL DATA, CLINICAL DECISION MAKING, TREATMENT PLANNING AND REPORT, AND INTERACTIVE FEEDBACK TO THE PATIENT, FAMILY MEMBER(S) OR CAREGIVER(S), WHEN PERFORMED; FIRST HOUR
Source: CMS coverage guidance
Coding guidelines
Common synonyms
Mild cognitive impairment of uncertain or unknown etiology
Frequently asked questions
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.