ICD-10-CM 2026 · Effective October 1, 2025

ICD-10 G20

Non-Billable Header

Parkinson's disease

G20
Block
4
Synonyms
0
LCDs
2
Payer Policies
2
Linked CPTs

About ICD-10-CM G20

ICD-10-CM code G20 represents Parkinson's disease. This is a non-billable header code in the Nervous System chapter (block G20). The 2026 edition of ICD-10-CM G20 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.

Inclusion Terms / Approximate Synonyms

Clinical terms and conditions classified under G20. Per CMS ICD-10-CM Tabular 2026.

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

Use Additional Code

When coding G20, also report these additional codes when applicable.

  • 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-)

Medicare LCD Coverage for G20

Local Coverage Determinations (LCDs) from CMS MACs that list G20 as a covered diagnosis.

No Medicare LCDs reference G20 as covered

This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.

Commercial Payer Coverage

Coverage policies from major commercial payers referencing G20.

2 policies

1 Cigna

Neuropsychological Testing - (EN0258)
Policy ID: EN_MM_0258

1 Humana

Diabetic Test Strips and Meters
Policy ID: HUM-090009298a3ac8d9

CPT Codes Commonly Billed with G20

Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.

2 linkages
  • 97112 Neuromuscular reeducation — hemiplegia, paraplegia, cerebral palsy, post-stroke, gait abnormality, ataxia, MS, Parkinson, concussion, hx TBI Physical Therapy
  • 97163 PT evaluation high complexity — hemiplegia, paraplegia, post-stroke, MS, Parkinson, TBI, fracture, post-replacement Physical Therapy

Convert G20 to ICD-9-CM

Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.

ICD-10ICD-9Mapping Flags
G20 3320 10000

Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).

ICD-10 G20, Billing FAQ

Is ICD-10 code G20 billable? +

No, G20 is a non-billable header code. Use a more specific child code from block G20 when submitting claims.

What other names or terms map to G20? +

ICD-10 G20 includes: Hemiparkinsonism; Idiopathic Parkinsonism or Parkinson's disease; Paralysis agitans, and 1 more clinical synonyms.

What CPT codes are commonly billed with G20? +

Procedures frequently paired with G20 include: 97112, 97163.

What ICD-9 codes does G20 map to? +

Per CMS GEMs, G20 maps to ICD-9 codes: 3320. Useful for legacy data review and historical claim analysis.

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Reviewed by the PayerReady Medical Coding Team

Verified against the CMS 2026 code set on June 1, 2026.

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