A Positron Emission Tomography (PET) scan is an advanced diagnostic imaging tool that measures metabolic activity within the body’s tissues and organs. Unlike other imaging techniques that primarily show anatomy, the PET scan uses a radioactive tracer, often a form of glucose, to visualize how cells are functioning. This procedure provides information at a cellular level, making it a standard tool for diagnosing and monitoring serious conditions. Medicare covers PET scans, but coverage is strictly conditional upon the service being deemed medically necessary for a specific, approved clinical indication.
Medicare Parts and General Coverage
Coverage for a PET scan falls under Original Medicare Part B, which is the medical insurance component responsible for outpatient services. Since the scan is typically performed on an outpatient basis, it is categorized as a diagnostic non-laboratory test. For Medicare to pay, the scan must be ordered by a treating physician and performed at a facility that accepts Medicare assignment.
Both the technical component (the scan itself) and the professional component (the radiologist’s interpretation) are processed through Part B. Private Medicare Advantage plans (Part C) must cover at least the same services as Original Medicare. However, beneficiaries in a Part C plan may face different rules regarding network requirements or mandatory pre-authorization before the scan.
Conditions Requiring Medical Necessity Review
Medicare’s payment for a PET scan depends on whether the service meets the strict criteria outlined in the National Coverage Determinations (NCDs) or Local Coverage Determinations (LCDs). These determinations, issued by the Centers for Medicare and Medicaid Services (CMS), define the specific diseases and clinical circumstances for which the scan is considered reasonable and necessary. The most common covered use is in oncology, where the scan helps in the diagnosis, staging, and restaging of solid tumors.
Established coverage includes specific cancers such as lung, colorectal, lymphoma, esophageal, and head and neck cancers. Coverage often dictates the number of scans allowed, such as one scan to determine the initial treatment strategy, followed by subsequent scans to monitor the response to therapy or check for recurrence. For example, a scan might be covered to evaluate the extent of a tumor before surgery but not for routine screening in a person without symptoms.
Beyond oncology, Medicare covers PET scans for evaluating myocardial viability in patients with coronary artery disease to determine if heart muscle is still alive and could benefit from revascularization. Coverage is also provided for certain neurological conditions, such as the differential diagnosis of specific dementias. CMS recently retired the restrictive NCD for amyloid PET imaging used in Alzheimer’s disease diagnosis, allowing local Medicare contractors to determine coverage. If a patient’s condition is not listed in these established coverage policies, payment may still be possible through a Coverage with Evidence Development (CED) program, which links payment to participation in a clinical study to gather more data.
Patient Financial Responsibility
Assuming a PET scan is approved and covered by Medicare Part B, the beneficiary is responsible for certain out-of-pocket costs. The first step is meeting the annual Part B deductible. Once the deductible has been satisfied, the patient is responsible for 20% of the Medicare-approved amount for the service. Medicare covers the remaining 80% of the approved charge.
The actual dollar amount of the 20% coinsurance can vary significantly depending on where the scan is performed. A scan performed in a hospital outpatient department will generally have a higher Medicare-approved charge than one conducted at a freestanding imaging center. If the scan is performed in a hospital outpatient setting, the patient may also be subject to a hospital copayment that could exceed the standard 20% coinsurance. Many beneficiaries rely on a Medicare Supplement Insurance policy (Medigap) or a secondary payer like Medicaid to cover this cost.
The Pre-Authorization and Appeals Process
Original Medicare does not typically require formal pre-authorization for a PET scan, though the facility may submit a request to confirm coverage for complex or less common indications. Medicare Advantage plans frequently mandate prior authorization for high-cost services like PET scans, so the patient or provider must confirm their specific plan requirements. The provider must ensure that medical documentation clearly supports one of the approved indications under the NCDs or LCDs.
If the provider believes Medicare will likely deny payment because the service does not meet the necessary criteria, they must issue an Advance Beneficiary Notice of Noncoverage (ABN) to the patient. This form must be signed before the service is rendered and informs the beneficiary of the specific reason for the expected denial and the estimated cost. By signing the ABN, the patient agrees to take on financial responsibility if Medicare denies the claim. If Medicare ultimately denies the claim, the beneficiary retains the right to appeal the decision through a multi-level process outlined on the Medicare Summary Notice (MSN).