G31.1 — Senile degeneration of brain, not elsewhere classified
Is G31.1 billable?
Yes, but G31.1 is an unspecified code. G31.1 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, G31.1 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting G31.1 — the more specific alternatives are listed below.
More specific alternatives
G31.1 at a glance
| Code | G31.1 |
|---|---|
| Description | Senile degeneration of brain, not elsewhere classified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does G31.1 group to?
G31.1 sits in MDC 01 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 056Degenerative Nervous System Disorders with MCCmedical
- 057Degenerative Nervous System Disorders without MCCmedical
How is G31.1 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to G31.1. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Degeneration, degenerative › motor centers, senile
- Atrophy, atrophic › brain › senile NEC (of)
- Degeneration, degenerative › brain › senile NEC
- Degeneration, degenerative › senile › brain
- Degeneration, degenerative › senile › motor centers
- Disease, diseased › brain › senile NEC
Excludes1 — never code together
The conditions below can never be reported together with G31.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Use additional code — inherited from G31
Report an additional code alongside G31.1 to fully describe the condition. G31.1 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 G31.1, but a patient may have both at the same time. When documentation supports it, G31.1 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 G31.1, but a patient may have both at the same time. When documentation supports it, G31.1 and the excluded code may both be reported.
- Reye's syndrome (G93.7)
How long has G31.1 existed?
G31.1 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.
Which codes are confused with G31.1?
ICD-10-CM declares these codes mutually exclusive with G31.1 — exactly one of each pair can be correct for a given encounter.