G21 G21 is a non-billable ICD-10 code for Secondary parkinsonism. It should not be used for HIPAA-covered transactions as a more specific code is available to choose from below.
↓ See below for any exclusions, inclusions or special notations
A more specific code should be selected. ICD-10-CM codes are to be used and reported at their highest number of characters available. A 3-character code is to be used only if it is not further subdivided. A code is invalid if it has not been coded to the full number of characters required for that code, including the 7th character, if applicable.
Select Billable Codes to view only billable codes under G21 or select the Tabular List to view all codes under G21 in hierarchical order.
Listed below are all Medicare Accepted ICD-10 codes under G21 for Secondary parkinsonism. These codes can be used for all HIPAA-covered transactions.
The codes listed below are in tabular order from G21. Codes marked as Billable can be used in all HIPAA-covered transactions.
ICD-10 code G21 is based on the following Tabular structure:
Chapter 6: Diseases of the nervous system
NEC Not elsewhere classifiable
This abbreviation in the Tabular List represents “other specified”. When a specific code is not available for a condition, the Tabular List includes an NEC entry under a code to identify the code as the “other specified” code.
NOS Not otherwise specified
This abbreviation is the equivalent of unspecified.
This note further define, or give examples of, the content of the code or category.
List of terms is included under some codes. 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.
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first, if applicable, followed by the manifestation. Wherever such a combination exists, there is a “use additional code” note at the etiology code, and a “code first” note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
A type 1 Excludes note is a pure excludes. It means 'NOT CODED HERE!' An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
A type 2 Excludes note represents 'Not included here'. An Excludes2 note indicates that the condition excluded is not part of the condition it is excluded from but a patient may have both conditions at the same time. When an Excludes2 note appears under a code it is acceptable to use both the code and the excluded code together.
A “code also” note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction. The sequencing depends on the circumstances of the encounter.
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first, if applicable, followed by the manifestation. Wherever such a combination exists, there is a “use additional code” note at the etiology code, and a “code first” note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.