G21 – Secondary parkinsonism
ICD-10-CM 2027 diagnosis code · Extrapyramidal and movement disorders
ICD-10-CM code
G21
- Code
G21(claims format:G21)- Description
- Secondary parkinsonism
- Billable
- No – use a more specific code below
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 6. Diseases of the nervous system (G00-G99)
- Block
- G20-G26 Extrapyramidal and movement disorders
Billable codes under G21
G21 is a header code and cannot be used on claims. Choose the most specific code:
- G21.0 – Malignant neuroleptic syndromeBillable
- G21.1 – Other drug-induced secondary parkinsonismHeader (more codes below)
- G21.2 – Secondary parkinsonism due to other external agentsBillable
- G21.3 – Postencephalitic parkinsonismBillable
- G21.4 – Vascular parkinsonismBillable
- G21.8 – Other secondary parkinsonismBillable
- G21.9 – Secondary parkinsonism, unspecifiedBillable
Notes for G21
Frequently asked questions
What is ICD-10 code G21?
G21 is the ICD-10-CM code for secondary parkinsonism, in the block G20-G26 (Extrapyramidal and movement disorders).
Is G21 a billable code?
No. G21 is a header code with more specific child codes; report one of the billable codes listed above.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.