Is G44.091 a billable ICD-10-CM code?

Yes. G44.091 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does G44.091 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 G44.091?

G44.091 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 G44.091 (G44) and apply to it just the same.

G44.091

G44.091 — Other trigeminal autonomic cephalgias (TAC), intractable

Billable / specific codeICD-10-CM

G44.091 is a billable, specific ICD-10-CM code for other trigeminal autonomic cephalgias (tac), intractable. It is valid for submission on a claim.

Excludes1 inherited from the categories above G44.091

These are not written on G44.091, but they bind it: a note on a category applies to every code beneath it. Billing G44.091 with anything listed here is a denial.

Written on G44 — Other headache syndromes

headache NOS (R51.9)

Excludes2 inherited from the categories above G44.091

Also inherited, and the opposite of Excludes1: these conditions are not part of G44.091, but a patient can have both, so you may code both.

Written on G44 — Other headache syndromes

atypical facial pain (G50.1)
headache due to lumbar puncture (G97.1)
migraines (G43.-)
trigeminal neuralgia (G50.0)

Risk adjustment

G44.091 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

G44.091 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.

A56612Billing and Coding: CT of the Head
A57204Billing and Coding: MRI and CT Scans of the Head and Neck

How G44.091 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 G44.091.

Horton's headache or neuralgia›intractable
TAC NEC›intractable
Cephalgia, cephalalgia›trigeminal autonomic NEC›intractable
Neuralgia, neuralgic›Horton's›intractable

Code history

G44.091 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share G44.09. If G44.091 is not quite right, the correct code is usually one of these.

G44.099Other trigeminal autonomic cephalgias (TAC), not intractable

Questions about G44.091

Is G44.091 a billable ICD-10-CM code?: Yes. G44.091 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does G44.091 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 G44.091?: G44.091 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 G44.091 (G44) and apply to it just the same.