G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations
G20.A1 is a billable, specific ICD-10-CM code for parkinson's disease without dyskinesia, without mention of fluctuations. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Parkinson's disease NOS
- Parkinson's disease without dyskinesia, without mention of OFF episodes
Other codes that can never be billed with G20.A1
These codes carry an Excludes1 note pointing at G20.A1. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading G20.A1 alone.
- G20.CParkinsonism, unspecified
Risk adjustment
G20.A1 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
G20.A1 is named in 26 Medicare coverage policies — 26 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52507External Infusion Pumps - Policy Article
- A53064Billing and Coding: Outpatient Occupational Therapy
- A53065Billing and Coding: Outpatient Physical Therapy
- A54095Billing and Coding: Nerve Conduction Studies and Electromyography
How G20.A1 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 G20.A1.
- Disease, diseased›Parkinson's
- Dementia›in›Parkinson's disease
- Dementia›with›Parkinson's disease
- Dementia›with›Parkinson's disease›with behavioral disturbance
- Disease, diseased›Parkinson's›without dyskinesia›without mention of›fluctuations
- Disease, diseased›Parkinson's›without dyskinesia›without mention of›OFF episodes
Related codes at this level
Codes that share G20.A. If G20.A1 is not quite right, the correct code is usually one of these.
Questions about G20.A1
- Is G20.A1 a billable ICD-10-CM code?
- Yes. G20.A1 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G20.A1 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Extrapyramidal and movement disorders (G20-G26).