2027 ICD-10-CM Diagnosis Code G20Parkinson's disease

ICD-10-CM Codes›G00–G99›G20-G26›G20

ICD-10-CM G20
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G20 is a non-billable ICD-10-CM category code for Parkinson's disease, so it cannot be submitted on claims. Use a more specific code from this category instead, such as G20.A1, G20.A2, G20.B1, and G20.B2. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parkinson's disease.

Code Identity

ICD-10-CM Code
G20
Billable Status
No — Non-Billable Category
Code Describes
Parkinson's disease
Short Description
Parkinson's disease
Same as the full description in the CMS dataset.
Chapter
G20-G26
Extrapyramidal and movement disorders

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG20-G26Extrapyramidal and movement disorders
CategoryG20Parkinson's disease
This CodeG20Parkinson's disease

Specific Coding for Parkinson's diseaseOverview

Non-specific codes like G20 require more characters. Use one of these billable codes instead:

  • G20.A for Parkinson's disease without dyskinesia

  • Use G20.A1 for Parkinson's disease without dyskinesia, without mention of fluctuations

  • Use G20.A2 for Parkinson's disease without dyskinesia, with fluctuations

  • G20.B for Parkinson's disease with dyskinesia

  • Use G20.B1 for Parkinson's disease with dyskinesia, without mention of fluctuations

  • Use G20.B2 for Parkinson's disease with dyskinesia, with fluctuations

  • Use G20.C for Parkinsonism, unspecified

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G20: its own notes plus those printed at Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

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

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Use Additional Code

Add a second code, after this one, to fully describe the condition.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G20, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming G20: they are not reported together with it, unless the two conditions are unrelated.

  • R25 Abnormal involuntary movements
    specific movement disorders (G20-G26)

Excludes2 1

These codes carry an Excludes2 note naming G20: its condition is not part of those codes, and both may be reported when the patient has both.

  • F98.4 Stereotyped movement disorders
    movement disorders of organic origin (G20-G25)

Code First 3

These codes say to code first a condition named in the note, and G20 is one of the conditions named.

  • F02 Dementia in other diseases classified elsewhere
    Parkinson's disease (G20.-)
  • F06.7 Mild neurocognitive disorder due to known physiological condition
    Parkinson's disease (G20.-)
  • R47.82 Fluency disorder in conditions classified elsewhere
    Parkinson's disease (G20.-)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS004
Parkinson's disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Parkinson Disease

    a progressive, degenerative neurologic disease characterized by a tremor that is maximal at rest, retropulsion (i.e. a tendency to fall backwards), rigidity, stooped posture, slowness of voluntary movements, and a masklike facial expression. pathologic features include loss of melanin containing neurons in the substantia nigra and other pigmented nuclei of the brainstem. lewy bodies are present in the substantia nigra and locus coeruleus but may also be found in a related condition (lewy body disease, diffuse) characterized by dementia in combination with varying degrees of parkinsonism. (adams et al., principles of neurology, 6th ed, p1059, pp1067-75)

Patient EducationClinical

Parkinson's Disease

Parkinson's disease (PD) is a type of movement disorder. It happens when nerve cells in the brain don't produce enough of a brain chemical called dopamine. Sometimes it is genetic, but most cases do not seem to run in families. Exposure to chemicals in the environment might play a role.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert G20 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
332.0 Paralysis agitans
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G20Overview

What is the ICD-10 code for Parkinson's disease?

G20 is the ICD-10-CM category for Parkinson's disease, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is G20 (Parkinson's disease) a billable code?

No. This is a category header that groups the codes for Parkinson's disease, and headers cannot be submitted on claims. Claims for Parkinson's disease need a more specific code from this category, such as G20.A1, G20.A2, and G20.B1.

Does G20 need an additional code?

When the condition applies, yes. The Use Additional Code note reads: 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); and 1 more listed in the Instructional Notes section. The additional code is reported after G20.

What is the ICD-9 equivalent of G20?

Under the General Equivalence Mappings, Parkinson's disease converts to ICD-9-CM 332.0 (paralysis agitans). The mapping is approximate, so confirm the match fits the documentation.