G21 ICD-10-CM Code: Secondary parkinsonism
A clear reference for the official code description, hierarchy, and related coding information from the FY 2027 U.S. release.
Official description
G21Secondary parkinsonism
ICD-10-CM diagnosis code · United States clinical modification
Where G21 sits
- 1
Chapter 6
Diseases of the nervous system (G00-G99)
- 2
Section
Extrapyramidal and movement disorders (G20-G26)
- 3
Category G21
Secondary parkinsonism
- 4
Code G21
Secondary parkinsonism
Codes under G21
G21 is a non-billable category. Choose the child code that best matches the documented diagnosis.
Notes for this code
Inclusion terms
No inclusion terms are listed for G21.
Code first
No “code first” instruction is listed for G21.
Use additional code
No “use additional code” instruction is listed for G21.
Excludes1
Conditions that should not be reported together with this code.
- Huntington's disease (G10)
- neurocognitive disorder with Lewy bodies (G31.83)
- Shy-Drager syndrome (G90.3)
- syphilitic Parkinsonism (A52.19)
Excludes2
Conditions not included here that may be reported separately when present.
No Excludes2 note is listed for G21.
Source and release
- Data release
- U.S. ICD-10-CM · FY 2027
- Effective date
- Oct 1, 2026
- Publisher
- Vero Scribe Inc.
This reference is generated from Vero’s ICD-10-CM description, hierarchy, and code-note dataset. The visible content and structured data share that source.
Frequently asked questions
What does ICD-10-CM code G21 mean?
G21 is the FY 2027 U.S. ICD-10-CM code for “Secondary parkinsonism.”
Is G21 a billable or specific ICD-10-CM code?
No. G21 has more specific child codes in the FY 2027 reference data. Select the code that matches the documentation and confirm the active code set and payer requirements.
Where is G21 located in ICD-10-CM?
G21 is listed in Chapter 6, Diseases of the nervous system (G00-G99), within Extrapyramidal and movement disorders (G20-G26) (G20–G26), under category G21, Secondary parkinsonism.
What coding notes are listed for G21?
No inclusion terms are listed for G21 in this reference record. No code-first instruction is listed. Excludes1 notes: Huntington's disease (G10); neurocognitive disorder with Lewy bodies (G31.83); Shy-Drager syndrome (G90.3); syphilitic Parkinsonism (A52.19). No Excludes2 note is listed.