G21.2 — Secondary parkinsonism due to other external agents
G21.2 is a billable, specific ICD-10-CM code for secondary parkinsonism due to other external agents. It is valid for submission on a claim.
Risk adjustment
G21.2 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
G21.2 is named in 12 Medicare coverage policies — 12 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
- A56621Billing and Coding: Swallowing Studies for Dysphagia
How G21.2 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 G21.2.
- Parkinsonism›secondary›due to›external agents NEC
Related codes at this level
Codes that share G21. If G21.2 is not quite right, the correct code is usually one of these.
Questions about G21.2
- Is G21.2 a billable ICD-10-CM code?
- Yes. G21.2 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G21.2 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Extrapyramidal and movement disorders (G20-G26).