G23.9 — Degenerative disease of basal ganglia, unspecified
G23.9 is a billable, specific ICD-10-CM code for degenerative disease of basal ganglia, unspecified. It is valid for submission on a claim.
Risk adjustment
G23.9 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 199 Parkinson and Other Degenerative Disease of Basal Ganglia0.615 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
G23.9 is named in 6 Medicare coverage policies — 6 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A54111Billing and Coding: Speech Language Pathology (SLP) Services: Communication Disorders
- A56612Billing and Coding: CT of the Head
- A56619Billing and Coding: Nerve Conduction Studies and Electromyography
- A56773Billing and Coding: Neurophysiology Evoked Potentials (NEPs)
How G23.9 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to G23.9.
- Degeneration, degenerative›basal nuclei or ganglia
- Disease, diseased›basal ganglia›degenerative
Related codes at this level
Codes that share G23. If G23.9 is not quite right, the correct code is usually one of these.
Questions about G23.9
- Is G23.9 a billable ICD-10-CM code?
- Yes. G23.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G23.9 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Extrapyramidal and movement disorders (G20-G26).