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G20 ICD-10-CM Code: Parkinson's disease

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Coding at a Glance

Tabular directives
4 inclusion terms · 7 use-additional codes

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G20 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Inclusion Terms

Alternative terms the tabular list files under this code.

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

Use Additional Code

Supplementary codes the tabular list directs you to add.

Coder workflow for G20

MedCoder structured workflow — derived from this code’s own official record

Before you code G20

  1. G20 is not reportable as written. Select the more specific code beneath it that the documentation supports. Codes are reported to the highest level of specificity the classification provides (Guidelines I.B.2).

    ReviewG20.A, G20.B, G20.C

    See the relationships section · Guide: How to choose an ICD-10-CM code →

Choose the right path

  1. Does the documentation support one of the more specific codes beneath G20?
    Yes → Select that code and continue the checks below on its own page.
    No → G20 cannot be reported as written; query for the specificity its subcategory needs.

    ReviewG20.A, G20.B, G20.C

Consider G20. Then work the Use Additional Code note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

  • Use Additional Code — after identifying G20(7 notes)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with G20 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewF02.84, F02.A4, F02.B4, F02.C4, F02.81, F02.A1

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with G20?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewF02.84, F02.A4, F02.B4, F02.C4, F02.81, F02.A1

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

Parkinson's disease is a non-billable ICD-10-CM category code (G20). A more specific billable subcode must be selected for claims submission.

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G20 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: R25 — Abnormal involuntary movements.

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 1 Excludes2 note: F98.4 — Stereotyped movement disorders.

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 3 Code First instructions across 2 chapters: F02 — Dementia in other diseases classified elsewhere, F06.7 — Mild neurocognitive disorder due to known physiological condition, R47.82 — Fluency disorder in conditions classified elsewhere.

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Clinical classification (AHRQ CCSR):NVS004 — Parkinson's disease (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Parkinson's disease).

G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations, G20.A2 — Parkinson's disease without dyskinesia, with fluctuations, G20.B1 — Parkinson's disease with dyskinesia, without mention of fluctuations, G20.B2 — Parkinson's disease with dyskinesia, with fluctuations, G20.C — Parkinsonism, unspecified

Contextual Map

Every relationship of G20 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run G20 with these 13 related codes in Claim Check

Hierarchy

Use Additional Code (21)

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code First instructions

Clinical classification (CCSR)

Nearest codes

Change history (2)

Common coding questions

Can G20 be billed directly?

No. G20 (Parkinson's disease) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Change history

  • FY2024 — October 1, 2023
    Became a non-billable header
    FY2024 changes
  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Parkinson's disease

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G20 in its code family, with their registry titles.