G47.421 — Narcolepsy in conditions classified elsewhere with cataplexy
G47.421 is a billable, specific ICD-10-CM code for narcolepsy in conditions classified elsewhere with cataplexy. It is valid for submission on a claim.
Risk adjustment
G47.421 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
G47.421 is named in 21 Medicare coverage policies — 17 listing it as supporting medical necessity, and 4 listing it as NOT covered. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56857Billing and Coding: MolDX: HLA-DQB1*06:02 Testing for Narcolepsynot covered
- A56881Billing and Coding: MolDX: HLA-DQB1*06:02 Testing for Narcolepsynot covered
- A57441Billing and Coding: MolDX: HLA-DQB1*06:02 Testing for Narcolepsynot covered
- A57575Billing and Coding: MolDX: HLA-DQB1*06:02 Testing for Narcolepsynot covered
How G47.421 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 G47.421.
- Narcolepsy›in conditions classified elsewhere›with cataplexy
Related codes at this level
Codes that share G47.42. If G47.421 is not quite right, the correct code is usually one of these.
Questions about G47.421
- Is G47.421 a billable ICD-10-CM code?
- Yes. G47.421 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G47.421 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Episodic and paroxysmal disorders (G40-G47).