Parkinson's disease (G20) ICD-10-CM
The G20 code range covers parkinson's disease with 8 ICD-10-CM diagnosis codes. 5 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
- Hemiparkinsonism
- Idiopathic Parkinsonism or Parkinson's disease
- Paralysis agitans
- Primary Parkinsonism or Parkinson's disease
Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an 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
Codes in the G20 Range 8 codes · 5 billable
- G20 Parkinson's diseaseNon-billable
- G20.A Parkinson's disease without dyskinesiaNon-billable
- 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 dyskinesiaNon-billable
- G20.B1 Parkinson's disease with dyskinesia, without mention of fluctuations
- G20.B2 Parkinson's disease with dyskinesia, with fluctuations
- G20.C Parkinsonism, unspecified
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the G20 range.
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)
Parkinsonian Disorders
A group of disorders which feature impaired motor control characterized by bradykinesia, MUSCLE RIGIDITY; TREMOR; and postural instability. Parkinsonian diseases are generally divided into primary parkinsonism (see PARKINSON DISEASE), secondary parkinsonism (see PARKINSON DISEASE, SECONDARY) and inherited forms. These conditions are associated with dysfunction of dopaminergic or closely related motor integration neuronal pathways in the BASAL GANGLIA.
About the G20 Code Range
Parkinson's disease is a progressive nervous system disease marked by symptoms such as a tremor at rest, stiffness, and slowed voluntary movement.
G20.A describes Parkinson's disease without dyskinesia, a movement disorder. G20.B describes Parkinson's disease with dyskinesia. Each group then separates cases with fluctuations from those without mention of fluctuations: G20.A1 and G20.B1 have no mention of fluctuations; G20.A2 and G20.B2 have fluctuations. G20.C is unspecified parkinsonism.
Questions About This Page
How many billable codes are in the G20 range?
Of the 8 codes in this range, 5 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the G20 range classify?
The range classifies parkinson's disease. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
