G90.9: Disorder of the autonomic nervous system, unspecified
G90.9, disorder of the autonomic nervous system, unspecified, is listed as a covered diagnosis in 3 Medicare billing and coding articles that apply to 10 HCPCS Level II codes, including G2187 (Patients with clinical indications for imaging of the…), G2188 (Patients with clinical indications for imaging of the…), G2189 (Patients with clinical indications for imaging of the…). The articles come from 2 Medicare contractors. A listed diagnosis supports medical necessity only; coverage still depends on the LCD's criteria and on documentation in the medical record.
HCPCS Level II codes with G90.9 as a covered diagnosis
| Code | Description | Medicare coverage | DMEPOS fee 2026 (state range) | Articles listing it |
|---|---|---|---|---|
| G2187 | Patients with clinical indications for imaging of the head: head trauma | Carrier judgment | — | 1 |
| G2188 | Patients with clinical indications for imaging of the head: new or change in headache above 50 years of age | Carrier judgment | — | 1 |
| G2189 | Patients with clinical indications for imaging of the head: abnormal neurologic exam | Carrier judgment | — | 1 |
| G2190 | Patients with clinical indications for imaging of the head: headache radiating to the neck | Carrier judgment | — | 1 |
| G2191 | Patients with clinical indications for imaging of the head: positional headaches | Carrier judgment | — | 1 |
| G2192 | Patients with clinical indications for imaging of the head: temporal headaches in patients over 55 years of age | Carrier judgment | — | 1 |
| G2193 | Patients with clinical indications for imaging of the head: new onset headache in pre-school children or younger (<6 years of age) | Carrier judgment | — | 1 |
| G2194 | Patients with clinical indications for imaging of the head: new onset headache in pediatric patients with disabilities for which headache is a concern as inferred from behavior | Carrier judgment | — | 1 |
| G2195 | Patients with clinical indications for imaging of the head: occipital headache in children | Carrier judgment | — | 1 |
| G0255 | Current perception threshold/sensory nerve conduction test, (snct) per limb, any nerve | Non-covered by Medicare | Not covered | 2 |
Medicare policy articles listing G90.9
- A57668: Billing and Coding: Nerve Conduction Studies and Electromyography (Wellpoint Federal (MAC - Part A, MAC - Part B); 1 Level II codes). LCD with the same title: L34594, L34859, L35048, L35081
- A56619: Billing and Coding: Nerve Conduction Studies and Electromyography (Palmetto GBA (MAC - Part A, MAC - Part B); 1 Level II codes). LCD with the same title: L34594, L34859, L35048, L35081
- A56612: Billing and Coding: CT of the Head (Palmetto GBA (MAC - Part A, MAC - Part B); 9 Level II codes). LCD with the same title: L34417
A diagnosis listed as covered in a billing and coding article supports medical necessity for the article's codes; it does not guarantee payment. Coverage depends on the LCD's criteria, the contractor's jurisdiction and documentation in the medical record.
Other G90 diagnoses (Disorders of autonomic nervous system)
- G90.01 — Carotid sinus syncope
- G90.09 — Other idiopathic peripheral autonomic neuropathy
- G90.2 — Horner's syndrome
- G90.4 — Autonomic dysreflexia
- G90.511 — Complex regional pain syndrome I of right upper limb
- G90.512 — Complex regional pain syndrome I of left upper limb
- G90.513 — Complex regional pain syndrome I of upper limb, bilateral
- G90.521 — Complex regional pain syndrome I of right lower limb
- G90.522 — Complex regional pain syndrome I of left lower limb
- G90.523 — Complex regional pain syndrome I of lower limb, bilateral
- G90.59 — Complex regional pain syndrome I of other specified site
- G90.89 — Other disorders of autonomic nervous system
Frequently asked questions
Does Medicare cover G90.9 (Disorder of the autonomic nervous system, unspecified)?
Medicare covers items and services, not diagnoses. 3 Medicare billing and coding articles list G90.9 as a covered diagnosis for 10 HCPCS Level II codes: the diagnosis can support medical necessity for those codes, but payment still depends on the LCD's coverage criteria and the medical record.
Which HCPCS codes can be billed with ICD-10 G90.9?
The Level II codes from the policies most specific to this diagnosis are G2187 (Patients with clinical indications for imaging of the…, 1 article); G2188 (Patients with clinical indications for imaging of the…, 1 article); G2189 (Patients with clinical indications for imaging of the…, 1 article); G2190 (Patients with clinical indications for imaging of the…, 1 article); G2191 (Patients with clinical indications for imaging of the…, 1 article). Code choice depends on the item supplied; check each code's descriptor.
Which Medicare policy articles list G90.9?
A57668 (Billing and Coding: Nerve Conduction Studies and Electromyography); A56619 (Billing and Coding: Nerve Conduction Studies and Electromyography); A56612 (Billing and Coding: CT of the Head).
What is ICD-10-CM code G90.9?
G90.9 is the ICD-10-CM code for disorder of the autonomic nervous system, unspecified, in category G90 (Disorders of autonomic nervous system), chapter 6: Diseases of the nervous system.
Next steps
- Run a reimbursement report for a device billed under G2187
- Watch G2187 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for G2187
Sources: CMS Medicare Coverage Database billing and coding articles (covered ICD-10 code lists and HCPCS links); ICD-10-CM FY2026; CMS HCPCS Level II release October 2026; CMS DMEPOS fee schedule 2026 (non-rural state fees). Not billing or legal advice.
Chapter 6: Diseases of the nervous system · All diagnoses · HCPCS lookup