2026 ICD-10-CM Diagnosis Code G31.84Mild cognitive impairment of uncertain or unknown etiology
ICD-10-CM Codes›G00–G99›G30-G32›G31
- Billable — Valid for Submission
- Chronic Condition
G31.84 is a billable ICD-10-CM diagnosis code for mild cognitive impairment of uncertain or unknown etiology. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as amnestic mild cognitive disorder. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neurocognitive disorders and Other nervous system disorders (often hereditary or degenerative).
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Amnestic mild cognitive disorder
- Mild neurocognitive disorder
- Neurocognitive disorder
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Mild cognitive disorder NOS
- Mild neurocognitive disorder of uncertain or unknown etiology
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
Type 1 Excludes
- 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
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- Disorder (of) - See Also: Disease;
- mild neurocognitive - G31.84
- neurocognitive - R41.9
- mild (of uncertain or unknown etiology) - See Also: Disorder, mild neurocognitive; - G31.84
- Impaired, impairment (function)
- cognitive, mild, of uncertain or unknown etiology - G31.84
- mild cognitive - G31.84
- of uncertain or unknown etiology - G31.84
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Disorder(of)
- mild neurocognitive
- Disorder(of)
- neurocognitive
- mild (of uncertain or unknown etiology)
- Impaired, impairment(function)
- cognitive, mild, of uncertain or unknown etiology
- Impaired, impairment(function)
- mild cognitive
- Impaired, impairment(function)
- mild cognitive
- of uncertain or unknown etiology
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Mild Cognitive Impairment
Some forgetfulness can be a normal part of aging. However, some people have more memory problems than other people their age. This condition is called mild cognitive impairment, or MCI. People with MCI can take care of themselves and do their normal activities.
The full article covers:
- What is Mild Cognitive Impairment?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert G31.84 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About G31.84Overview
Is G31.84 (Other specified degenerative diseases of nervous system) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report mild cognitive impairment of uncertain or unknown etiology on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What is the ICD-9 equivalent of G31.84?
Under the General Equivalence Mappings, mild cognitive impairment of uncertain or unknown etiology converts to ICD-9-CM 331.83 (mild cognitive impairemt). The mapping is a direct match.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
