G31.8 — Other specified degenerative diseases of nervous system
Is G31.8 billable?
No — G31.8 is a non-billable header code. G31.8 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 9 billable codes beneath G31.8.
Billable codes under this header
- G31.80Leukodystrophy, unspecified
- G31.81Alpers disease
- G31.82Leigh's disease
- G31.83Neurocognitive disorder with Lewy bodies
- G31.84Mild cognitive impairment of uncertain or unknown etiology
- G31.85Corticobasal degeneration
- G31.86Alexander disease
- G31.87Primary progressive apraxia of speech
- G31.89Other specified degenerative diseases of nervous system
G31.8 at a glance
| Code | G31.8 |
|---|---|
| Description | Other specified degenerative diseases of nervous system |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Use additional code — inherited from G31
Report an additional code alongside G31.8 to fully describe the condition. G31.8 is sequenced first.
- 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-)
Excludes2 — not included here — inherited from Chapter 6
The conditions below are not part of G31.8, but a patient may have both at the same time. When documentation supports it, G31.8 and the excluded code may both be reported.
- 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)
Excludes2 — not included here — inherited from G31
The conditions below are not part of G31.8, but a patient may have both at the same time. When documentation supports it, G31.8 and the excluded code may both be reported.
- Reye's syndrome (G93.7)
What codes fall under G31.8? (9)
- G31.80Leukodystrophy, unspecified
- G31.81Alpers disease
- G31.82Leigh's disease
- G31.83Neurocognitive disorder with Lewy bodies
- G31.84Mild cognitive impairment of uncertain or unknown etiology
- G31.85Corticobasal degeneration
- G31.86Alexander disease
- G31.87Primary progressive apraxia of speech
- G31.89Other specified degenerative diseases of nervous system
How long has G31.8 existed?
G31.8 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.