Is G21 a billable code?
No. G21 is a header code that groups 8 more specific codes. Use one of the billable codes listed on this page instead.
ICD-10-CM FY2027 diagnosis code
G21: Secondary parkinsonism
Header code: not billableValid for dates of service October 1, 2026 to September 30, 2027
G21 groups related diagnoses under secondary parkinsonism. It cannot be used on a claim by itself. Choose the billable code below that matches the patient's record.
Billable codes under G21
- G21.0Malignant neuroleptic syndrome
- G21.11Neuroleptic induced parkinsonism
- G21.19Other drug induced secondary parkinsonism
- G21.2Secondary parkinsonism due to other external agents
- G21.3Postencephalitic parkinsonism
- G21.4Vascular parkinsonism
- G21.8Other secondary parkinsonism
- G21.9Secondary parkinsonism, unspecified
G21 questions
What does G21 mean?
G21 is the ICD-10-CM code for Secondary parkinsonism. It is in chapter 6, Diseases of the nervous system (G00-G99).
Code titles come from the official ICD-10-CM files published by the CDC National Center for Health Statistics. Always check payer rules and the clinical record before billing.