G99.8 — Other specified disorders of nervous system in diseases classified elsewhere
G99.8 is a billable, specific ICD-10-CM code for other specified disorders of nervous system in diseases classified elsewhere. It is valid for submission on a claim.
Excludes1 — never code together
These conditions cannot occur together. Billing both on the same encounter is a denial.
Code first
The underlying condition must be sequenced before this code.
Risk adjustment
G99.8 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Medicare coverage
G99.8 is named in 2 Medicare coverage policies — 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A57204Billing and Coding: MRI and CT Scans of the Head and Neck
- A57206Billing and Coding: Lumbar MRI
Related codes at this level
Codes that share G99. If G99.8 is not quite right, the correct code is usually one of these.
Questions about G99.8
- Is G99.8 a billable ICD-10-CM code?
- Yes. G99.8 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G99.8 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Other disorders of the nervous system (G89-G99).
- What cannot be coded together with G99.8?
- G99.8 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.