G04.91 — Myelitis, unspecified
G04.91 is a billable, specific ICD-10-CM code for myelitis, unspecified. It is valid for submission on a claim.
Risk adjustment
G04.91 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 182 Spinal Cord Disorders/Injuries0.478 RAF
Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.
Medicare coverage
G04.91 is named in 10 Medicare coverage policies — 10 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56551Billing and Coding: Visual Fields Testing
- A56619Billing and Coding: Nerve Conduction Studies and Electromyography
- A56695Billing and Coding: Implantable Infusion Pump
- A56799Billing and Coding: Visual Fields Testing
How G04.91 is indexed
Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to G04.91.
- Myelitis(acute) (ascending) (childhood) (chronic) (descending) (diffuse) (disseminated) (idiopathic) (pressure) (progressive) (spinal cord) (subacute)
- Myeloradiculitis
- Infection, infected, infective›spinal cord NOS
Related codes at this level
Codes that share G04.9. If G04.91 is not quite right, the correct code is usually one of these.
Questions about G04.91
- Is G04.91 a billable ICD-10-CM code?
- Yes. G04.91 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G04.91 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Inflammatory diseases of the central nervous system (G00-G09).