G40.843 — KCNQ2-related epilepsy, intractable, with status epilepticus
G40.843 is a billable, specific ICD-10-CM code for kcnq2-related epilepsy, intractable, with status epilepticus. It is valid for submission on a claim.
Excludes1 inherited from the categories above G40.843
These are not written on G40.843, but they bind it: a note on a category applies to every code beneath it. Billing G40.843 with anything listed here is a denial.
Excludes2 inherited from the categories above G40.843
Also inherited, and the opposite of Excludes1: these conditions are not part of G40.843, but a patient can have both, so you may code both.
Other codes that can never be billed with G40.843
These codes carry an Excludes1 note pointing at G40.843. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading G40.843 alone.
Risk adjustment
G40.843 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:
- HCC 201 Seizure Disorders and Convulsions0.245 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
G40.843 is named in 7 Medicare coverage policies — 7 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.
- A56612Billing and Coding: CT of the Head
- A56619Billing and Coding: Nerve Conduction Studies and Electromyography
- A56771Billing and Coding: Special Electroencephalography
- A56868Billing and Coding: Outpatient Speech Language Pathology
How G40.843 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 G40.843.
- Epilepsy, epileptic, epilepsia›KCNQ2-related›intractable›with status epilepticus
Code history
What changed, and when. Derived by diffing consecutive CMS release files — which matters when you are defending a code assigned under an earlier edition.
- addedFY2024-FY2026
KCNQ2-related epilepsy, intractable, with status epilepticus
Related codes at this level
Codes that share G40.84. If G40.843 is not quite right, the correct code is usually one of these.
Questions about G40.843
- Is G40.843 a billable ICD-10-CM code?
- Yes. G40.843 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does G40.843 sit in the tabular list?
- Diseases of the nervous system (G00-G99), in the block Episodic and paroxysmal disorders (G40-G47).
- What cannot be coded together with G40.843?
- G40.843 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above G40.843 (G40) and apply to it just the same.