G12.21 — Amyotrophic lateral sclerosis
G12.21 is a billable, specific ICD-10-CM code for amyotrophic lateral sclerosis. It is valid for submission on a claim.
Other codes that can never be billed with G12.21
These codes carry an Excludes1 note pointing at G12.21. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading G12.21 alone.
- M62.5Muscle wasting and atrophy, not elsewhere classified
Risk adjustment
G12.21 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 190 Amyotrophic Lateral Sclerosis and Other Motor Neuron Disease, Spinal Muscular Atrophy1.175 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
G12.21 is named in 31 Medicare coverage policies — 31 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A52494High Frequency Chest Wall Oscillation Devices - Policy Article
- A52510Mechanical In-exsufflation Devices - Policy Article
- A52996Billing and Coding: Routine Foot Care
- A53057Billing and Coding: Home Health Occupational Therapy
How G12.21 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 G12.21.
- Duchenne-Aran muscular atrophy
- Amyotrophia, amyotrophy, amyotrophic›lateral sclerosis
- Atrophy, atrophic›Duchenne-Aran
- Paralysis, paralytic›amyotrophic
- Sclerosis, sclerotic›amyotrophic(lateral)
- Sclerosis, sclerotic›lateral(amyotrophic) (descending) (spinal)
- Atrophy, atrophic›muscle, muscular›Duchenne-Aran
- Atrophy, atrophic›muscle, muscular›progressive(bulbar)
- Disease, diseased›motor neuron›amyotrophic lateral sclerosis
- Paralysis, paralytic›muscle, muscular NEC›progressive
- Paralysis, paralytic›spinal›progressive
- Sclerosis, sclerotic›spinal›lateral(amyotrophic)
Related codes at this level
Codes that share G12.2. If G12.21 is not quite right, the correct code is usually one of these.
Questions about G12.21
- Is G12.21 a billable ICD-10-CM code?
- Yes. G12.21 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G12.21 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Systemic atrophies primarily affecting the central nervous system (G10-G14).