TL;DR: The Centers for Medicare & Medicaid Services retired NCD 160.22 governing ambulatory EEG monitoring, effective January 1, 2023 — and CMS formally documented that retirement in NCD 215 with a March 7, 2026 update. If your team still treats this as an active national coverage determination, you're working from the wrong framework.
The CMS ambulatory EEG monitoring coverage policy no longer exists at the national level. NCD 215 confirms that NCD 160.22 was retired effective January 1, 2023, with implementation on April 10, 2023. There are no specific CPT or HCPCS codes listed in this policy document. Coverage determinations for ambulatory EEG monitoring — including 24-hour cassette-based electroencephalographic recording — now fall to your Medicare Administrative Contractor.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS |
| Policy | Ambulatory EEG Monitoring — RETIRED |
| Policy Code | NCD 215 (formerly NCD 160.22) |
| Change Type | Modified (retirement documented) |
| Effective Date | January 1, 2023 (NCD retirement); NCD 215 updated March 7, 2026 |
| Impact Level | High — national coverage framework removed; MAC-level rules now govern |
| Specialties Affected | Neurology, epilepsy programs, outpatient diagnostic testing facilities |
| Key Action | Identify your MAC's local coverage determination for ambulatory EEG and align your billing guidelines to that LCD immediately |
CMS Ambulatory EEG Monitoring Coverage Criteria and Medical Necessity Requirements 2026
Here's the core reality: CMS no longer sets national medical necessity rules for ambulatory EEG monitoring. NCD 160.22 governed this service for years. It defined ambulatory, or 24-hour electroencephalographic monitoring as a cassette recorder that continuously records brain wave patterns during a patient's routine daily activities and sleep. The equipment includes an electrode set, preamplifiers, and a cassette recorder worn on a belt.
That national framework is gone. CMS retired NCD 160.22 on January 1, 2023. The March 7, 2026 update to NCD 215 formally documents that retirement and points billing teams to claims processing instructions for any remaining questions.
What does retirement mean in practice? It means there is no active CMS coverage policy dictating whether ambulatory EEG monitoring is covered or not covered at the national level. The Centers for Medicare & Medicaid Services handed that authority to individual Medicare Administrative Contractors. Your MAC now sets the medical necessity criteria, documentation requirements, and any prior authorization requirements for this service in your region.
This is not a small administrative footnote. If your team has been billing ambulatory EEG monitoring based on the old NCD 160.22 criteria, you're now operating without a national safety net. A claim denial based on medical necessity — or a post-payment audit — won't be resolved by pointing to a retired NCD.
CMS Ambulatory EEG Monitoring Exclusions and Non-Covered Indications
NCD 215 does not list specific exclusions or non-covered indications. That's consistent with retirement — the national coverage policy has been removed, not replaced with a narrower one. Coverage determinations, including what's considered experimental or investigational, now come from your MAC's local coverage determination.
The real issue here is that "no national exclusions" does not mean "everything is covered." It means your MAC decides. Some MACs will have active LCDs for ambulatory EEG monitoring. Others may not. Where no LCD exists, coverage falls under your MAC's general medical necessity standard — and that's a harder case to win on appeal if a claim gets denied.
Coverage Indications at a Glance
Because NCD 160.22 is retired and NCD 215 contains no active indication-level criteria, there are no coverage indications to document at the national level. The table below reflects the current state of this policy.
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Ambulatory (24-hour) EEG monitoring — cassette-based | No national coverage determination | None listed in NCD 215 | Coverage governed by MAC LCD; check your regional contractor |
| Ambulatory EEG monitoring — all other methods | No national coverage determination | None listed in NCD 215 | NCD 160.22 retired January 1, 2023; MAC rules apply |
If you need indication-level coverage criteria, go to your MAC's website and pull their LCD for EEG monitoring. That document is now your primary coverage reference — not CMS's NCD database.
CMS Ambulatory EEG Monitoring Billing Guidelines and Action Items 2026
The March 7, 2026 update makes the retirement of NCD 160.22 formally part of NCD 215. Your billing team should treat this as a prompt to audit your current workflows, not a change that's still pending.
| # | Action Item |
|---|---|
| 1 | Find your MAC's LCD for ambulatory EEG monitoring now. Go to the CMS Coverage Database, filter by your MAC, and search for EEG monitoring LCDs. If your MAC has an active LCD, that document sets your medical necessity criteria, covered diagnoses, and documentation requirements. If no LCD exists, request coverage guidance from your MAC directly before billing. |
| 2 | Audit any open claims or pending appeals that reference NCD 160.22. If your team cited the retired NCD as the coverage basis, update your appeal language to reference the applicable MAC LCD or general Medicare medical necessity standards. Appeals built on a retired NCD will fail. |
| 3 | Update your charge capture documentation templates. Remove any reference to NCD 160.22 as the governing policy. If your charge capture or prior authorization workflow references this NCD, it needs to reflect that the coverage policy now sits with your MAC. |
| 4 | Verify whether your MAC requires prior authorization for ambulatory EEG monitoring. The retired NCD had no prior authorization requirement documented at the national level. Your MAC may have its own prior auth rules in place. Check the LCD and your MAC's billing guidelines before scheduling services. |
| 5 | Brief your neurology or epilepsy program on the documentation change. The clinical staff ordering ambulatory EEG monitoring need to know that medical necessity justification now maps to MAC criteria — not a CMS NCD. Their documentation needs to support the diagnosis codes and indications your MAC's LCD specifies. |
| 6 | Check for reimbursement rate changes at the MAC level. Retirement of a national coverage determination can coincide with fee schedule adjustments at the MAC level. Confirm your current reimbursement rates for ambulatory EEG monitoring codes with your MAC's fee schedule — don't assume the rates stayed the same. |
| 7 | Set a calendar reminder to recheck MAC LCDs quarterly. Without a national NCD governing this service, local coverage determinations are your only early warning system for coverage changes. MACs update LCDs independently and on their own timelines. Build a check into your quarterly policy review cycle. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Ambulatory EEG Monitoring Under NCD 215
NCD 215 does not list specific CPT, HCPCS, or ICD-10 codes. This is consistent with the retirement of NCD 160.22 — when CMS removes a national coverage determination, the associated national code list goes with it.
Covered CPT Codes (When Selection Criteria Are Met)
No CPT codes are listed in NCD 215. Your applicable codes for ambulatory EEG billing are governed by your MAC's LCD. Contact your MAC or review their LCD documentation for the specific CPT codes they recognize for 24-hour electroencephalographic monitoring and cassette-based EEG recording.
Key ICD-10-CM Diagnosis Codes
No ICD-10-CM codes are listed in NCD 215. Your MAC's LCD will specify the covered diagnosis codes. Typical diagnoses associated with ambulatory EEG monitoring — such as epilepsy, seizure disorders, and syncope workups — should be documented against your MAC's specific LCD criteria, not an assumed national standard.
A note on this policy's complexity: The absence of codes in NCD 215 is not a gap in the policy document. It reflects a deliberate structural reality — CMS retired the national coverage framework and did not replace it with a new one. If your billing team or compliance officer needs clarity on how this applies to your specific payer mix or patient population, talk to your compliance officer or a revenue cycle consultant before relying on any assumed code-level coverage. The effective date of this formal documentation is March 7, 2026, but the underlying retirement has been in place since January 1, 2023. If you haven't already adjusted your workflows, that's the more urgent conversation to have.
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