G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations
Is G20.A1 billable?
Yes — G20.A1 is billable for FY2027. G20.A1 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. G20.A1 may be submitted for encounters from October 1, 2026 through September 30, 2027.
G20.A1 at a glance
| Code | G20.A1 |
|---|---|
| Description | Parkinson's disease without dyskinesia, without mention of fluctuations |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does G20.A1 group to?
G20.A1 sits in MDC 01 and helps define the logic of 2 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 056Degenerative Nervous System Disorders with MCCmedical
- 057Degenerative Nervous System Disorders without MCCmedical
How is G20.A1 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to G20.A1. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Disease, diseased › Parkinson's
- Dementia › with › Parkinson's disease (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)
- Dementia › in › Parkinson's disease (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)
- Dementia › with › Parkinson's disease › with behavioral disturbance (degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)
- Disease, diseased › Parkinson's › without dyskinesia › without mention of › fluctuations
- Disease, diseased › Parkinson's › without dyskinesia › without mention of › OFF episodes
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)
How long has G20.A1 existed?
G20.A1 first appears in FY2024.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.