G21 — Secondary parkinsonism
Is G21 billable?
No — G21 is a non-billable header code. G21 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 8 billable codes beneath G21.
Billable codes under this header
- G21.0Malignant neuroleptic syndrome
- G21.2Secondary parkinsonism due to other external agents
- G21.3Postencephalitic parkinsonism
- G21.4Vascular parkinsonism
- G21.8Other secondary parkinsonism
- G21.9Secondary parkinsonism, unspecified
- G21.11Neuroleptic induced parkinsonism
- G21.19Other drug induced secondary parkinsonism
G21 at a glance
| Code | G21 |
|---|---|
| Description | Secondary parkinsonism |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Excludes1 — never code together
The conditions below can never be reported together with G21 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from Chapter 6
The conditions below are not part of G21, but a patient may have both at the same time. When documentation supports it, G21 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)
What codes fall under G21? (7)
How long has G21 existed?
G21 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with G21?
ICD-10-CM declares these codes mutually exclusive with G21 — exactly one of each pair can be correct for a given encounter.