G20.C Parkinsonism, unspecified

Billable ICD-10-CM code, FY2026.

Applicable to

• Parkinsonism, NOS

Excludes1 (never code together)

• Parkinson's disease NOS (G20.A1)
• Parkinson's disease with dyskinesia (G20.B-)
• Parkinson's disease without dyskinesia (G20.A-)
• secondary parkinsonism (G21.-)

Applies from G20 Parkinson's disease

Applicable to

• Hemiparkinsonism
• Idiopathic Parkinsonism or Parkinson's disease
• Paralysis agitans
• Primary Parkinsonism or Parkinson's disease

Use additional code

• code, if applicable, to identify:
• dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
• dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
• dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
• dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
• dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
• mild neurocognitive disorder due to known physiological condition (F06.7-)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 199 — Parkinson and Other Degenerative Disease of Basal Ganglia
• CMS-HCC V22: HCC 78 — Parkinson's and Huntington's Diseases
• RxHCC V08: HCC 161 — Parkinson Disease
• ESRD V24: HCC 78

MS-DRG index

Defines the logic of DRG(s) 056-057 in MDC 01.

Code annotations containing back-references to G20.C

Back-references to G20

• Code First: F02 Dementia in other diseases classified elsewhere ("Parkinson's disease (G20.-)")
• Code First: F06.7 Mild neurocognitive disorder due to known physiological condition ("Parkinson's disease (G20.-)")
• Type 2 Excludes: F98.4 Stereotyped movement disorders ("movement disorders of organic origin (G20-G25)")
• Type 1 Excludes: R25 Abnormal involuntary movements ("specific movement disorders (G20-G26)")
• Code First: R47.82 Fluency disorder in conditions classified elsewhere ("Parkinson's disease (G20.-)")

Diagnosis Index entries for G20.C

• Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety) › with › Parkinsonism
• Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety) › with › Parkinsonism › with behavioral disturbance
• Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety) › in (due to) › paralysis agitans
• Dementia (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety) › in (due to) › paralysis agitans › with behavioral disturbance
• Hemiparkinsonism
• Paralysis, paralytic (complete) (incomplete) › agitans
• Parkinsonism (idiopathic) (primary)
• Parkinsonism (idiopathic) (primary) › dementia
• Parkinsonism (idiopathic) (primary) › dementia › with behavioral disturbance
• Pyramidopallidonigral syndrome
• Syndrome › pyramidopallidonigral

Nearby codes

• G20.A1 Parkinson's disease without dyskinesia, without mention of fluctuations
• G20.A2 Parkinson's disease without dyskinesia, with fluctuations
• G20.B Parkinson's disease with dyskinesia
• G20.B1 Parkinson's disease with dyskinesia, without mention of fluctuations
• G20.B2 Parkinson's disease with dyskinesia, with fluctuations
• G20.C Parkinsonism, unspecified (this code)