FDG PET for Refractory Seizures | CMS Coverage Update

Summary: The Centers for Medicare & Medicaid Services modified its FDG PET for Refractory Seizures coverage policy, effective May 15, 2026. Here's what billing teams need to do before that date.

CMS FDG PET coverage policy for refractory seizures has a history of strict medical necessity criteria — and this modification signals that CMS is tightening how it defines covered indications. The policy does not list specific CPT or HCPCS codes in the available documentation, so billing teams will need to reference the full NCD language and their Medicare Administrative Contractor's local guidance for the precise code set. If your practice bills FDG PET scans for epilepsy patients, this change is worth your full attention before May 15, 2026.

Quick-Reference Table

CMS FDG PET Refractory Seizures Coverage Criteria and Medical Necessity Requirements 2026

The CMS FDG PET coverage policy for refractory seizures has always been one of the more specific coverage determinations in the nuclear imaging space. CMS covers FDG PET for seizure evaluation under narrow conditions — and this modification updates those conditions. The core question your billing team needs to answer is whether your patients and your documentation meet the revised criteria.

Under the existing national framework, Medicare covers FDG PET for refractory seizures when the scan is used for pre-surgical evaluation in patients with epilepsy that has failed to respond to adequate trials of antiepileptic medication. That "refractory" threshold matters enormously for medical necessity. If you can't document treatment failure clearly in the record, you're building a claim denial waiting to happen.

This modification reinforces CMS's position that FDG PET is not a first-line diagnostic tool. It's a late-stage evaluation tool for surgical candidates. The patient's clinical history, prior medication trials, and neurological workup must be in the record before the scan — not added after the fact to justify a claim.

Prior authorization requirements vary by Medicare Advantage plan. If your patients are on Medicare Advantage rather than traditional fee-for-service Medicare, confirm prior auth requirements with each plan individually. The national coverage determination governs traditional Medicare, but Medicare Advantage plans can layer on additional requirements.

The effective date of May 15, 2026 means you have a defined window to update your intake workflows, documentation templates, and order review processes. Don't wait until claims start getting flagged.

CMS FDG PET Refractory Seizures Exclusions and Non-Covered Indications

CMS does not cover FDG PET for general seizure workup or for patients whose epilepsy has not been deemed refractory. This distinction drives a significant share of claim denials in this space. "Seizure disorder" on the diagnosis line is not enough. The clinical record needs to show the patient has failed medical management.

FDG PET for seizure localization in patients who are not surgical candidates is also not covered. CMS covers this scan to help surgeons plan a resection. If surgery isn't on the table — because of the patient's condition, age, or other contraindications — the medical necessity argument collapses.

Routine follow-up PET scans after epilepsy surgery fall outside the covered indication as well. The coverage is for pre-surgical planning, not post-surgical monitoring. If your team has been billing follow-up FDG PET under this indication, stop and audit those claims now.

Coverage Indications at a Glance

The policy documentation available does not include a granular indication-by-indication breakdown with specific codes. The table below reflects the general coverage framework for CMS FDG PET in the refractory seizures context, based on the CMS national coverage determination structure.

CMS FDG PET Refractory Seizures Billing Guidelines and Action Items 2026

The modification is live May 15, 2026. Here's what your billing team and ordering providers need to do before then.

CPT, HCPCS, and ICD-10 Codes for FDG PET Refractory Seizures Under This Policy

The policy documentation provided does not list specific CPT, HCPCS, or ICD-10 codes. This is an important gap. Do not rely on general knowledge alone to determine which codes are covered under this modified policy.

What to Do Instead

Contact the Centers for Medicare & Medicaid Services directly, or check your MAC's website, for the current code set tied to FDG PET coverage for refractory seizures. The full policy is available at the CMS source document. Your MAC's LCD — if one exists for your region — will list the covered ICD-10 diagnosis codes required to support FDG PET billing for epilepsy.

General FDG PET Billing Context (for reference — confirm codes against the actual policy)

In general, FDG PET billing for neurological indications uses PET scan procedure codes and radiopharmaceutical supply codes. However, because this policy does not specify codes and CMS coverage determinations can be code-specific, your billing team must verify the exact codes against the official CMS policy document before billing. Building a charge capture workflow around assumed codes is a fast path to systematic denials.

The ICD-10 diagnosis codes supporting medical necessity for refractory epilepsy are particularly important here. CMS and MACs commonly require that diagnosis codes reflect both the epilepsy type and its refractory status. Your clinical documentation team and coders need to agree on the right ICD-10 selection before claims go out the door.

Ask your MAC's provider relations team specifically: which ICD-10 codes will support FDG PET medical necessity under this updated policy? Get that answer in writing, or at minimum note the date, time, and name of the person you spoke with.