G31.84
Mild cognitive impairment of uncertain or unknown etiology
G31.84 (also written G3184) is a billable ICD-10-CM diagnosis code for mild cognitive impairment of uncertain or unknown etiology. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 14 codes in category G31 (Other degenerative diseases of nervous system, not elsewhere classified). The Alphabetic Index lists it under 5 entries. Its coding notes include a Use additional code instruction, 11 Excludes1 entries and 9 Excludes2 entries.
Use additional code
Add the listed code as a secondary code, if known.
- 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-)
Excludes1
Not coded here. The listed conditions generally should not be reported 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)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
- Reye's syndrome (G93.7)
Also from chapter/block level (8 notes)
- 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)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Neuro Rehabilitation clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026IPF Primary
IPF MS-DRG adjustment. A principal diagnosis of this code groups to one of these MS-DRGs. Which one depends on other facts of the stay, so the factor is a range:
| MS-DRG | Description | Factor |
|---|---|---|
| 056 | Degenerative nervous system disorders w MCC | 1.12 |
| 057 | Degenerative nervous system disorders w/o MCC | 1.11 |
Inclusion terms
Conditions classified to this code.
- Mild cognitive disorder NOS
- Mild neurocognitive disorder of uncertain or unknown etiology
Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 5 entries
- 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