ICD-10 Code for Parkinson's Disease
The ICD-10-CM code for parkinson's disease is G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations. It is billable for FY2027.
Parkinson's disease ICD-10 codes at a glance
| Condition | Parkinson's disease |
|---|---|
| Code | G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations |
| Billable | Yes (G20.A1) |
| Alphabetic Index entry | Disease, diseased, Parkinson's |
| Code set | ICD-10-CM FY2027, valid October 1, 2026 – September 30, 2027 |
What changes the parkinson's disease code?
The Alphabetic Index lists these qualifiers under Disease, diseased, Parkinson's, with dyskinesia and Disease, diseased, Parkinson's, without dyskinesia. If the record documents one of them, the code changes. Verify the code in the Tabular List before reporting it.
| Disease, diseased, Parkinson's, with dyskinesia | ||
|---|---|---|
| with › fluctuations | G20.B2 | Parkinson's disease with dyskinesia, with fluctuations |
| with › OFF episodes | G20.B2 | Parkinson's disease with dyskinesia, with fluctuations |
| without mention of › fluctuations | G20.B1 | Parkinson's disease with dyskinesia, without mention of fluctuations |
| without mention of › OFF episodes | G20.B1 | Parkinson's disease with dyskinesia, without mention of fluctuations |
| Disease, diseased, Parkinson's, without dyskinesia | ||
| with › fluctuations | G20.A2 | Parkinson's disease without dyskinesia, with fluctuations |
| with › OFF episodes | G20.A2 | Parkinson's disease without dyskinesia, with fluctuations |
| without mention of › fluctuations | G20.A1 | Parkinson's disease without dyskinesia, without mention of fluctuations |
| without mention of › OFF episodes | G20.A1 | Parkinson's disease without dyskinesia, without mention of fluctuations |
What else changes the parkinson's disease code?
G20 splits on dyskinesia and motor fluctuations, not severity. As with Alzheimer's, an additional code from F02.8- identifies dementia and its features when the record documents cognitive decline alongside the motor disease.
Distinct from parkinsonism (G21.-), used when a specific secondary cause — drugs, encephalitis, arteriosclerosis — is documented instead of idiopathic Parkinson's disease.
What does the Tabular List say about G20.A1?
The instructional notes that govern G20.A1, including those it inherits from its category and chapter. An Excludes1 note means the two codes are never reported together.
Inclusion terms
Alternative wording in documentation that is classified to G20.A1.
- Parkinson's disease NOS
- Parkinson's disease without dyskinesia, without mention of OFF episodes
Use additional code — inherited from G20
Report an additional code alongside G20.A1 to fully describe the condition. G20.A1 is sequenced first.
- 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-)
Excludes2 — not included here — inherited from Chapter 6
The conditions below are not part of G20.A1, but a patient may have both at the same time. When documentation supports it, G20.A1 and the excluded code may both be reported.
- 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)
Codes, descriptions and Index entries are from the official ICD-10-CM FY2027 release. Guideline text is quoted from the ICD-10-CM Official Guidelines for Coding and Reporting FY 2027. A code must always be verified in the Tabular List before it is reported. Data sources