G31.85 — Corticobasal degeneration

Billable

Is G31.85 billable?

Yes — G31.85 is billable for FY2027. G31.85 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. G31.85 may be submitted for encounters from October 1, 2026 through September 30, 2027.

G31.85 at a glance

Code	G31.85
Description	Corticobasal degeneration
Billable	Yes
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

Which MS-DRGs does G31.85 group to?

G31.85 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 G31.85 listed in the Alphabetic Index?

These are the routes through the Alphabetic Index that lead to G31.85. They show the wording a clinician may have documented, which often differs from the Tabular description.

Degeneration, degenerative › corticobasal

Use additional code — inherited from G31

Report an additional code alongside G31.85 to fully describe the condition. G31.85 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 G31.85, but a patient may have both at the same time. When documentation supports it, G31.85 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 G31.85, but a patient may have both at the same time. When documentation supports it, G31.85 and the excluded code may both be reported.

Reye's syndrome (G93.7)

How long has G31.85 existed?

G31.85 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.