A computed tomography (CT) scan uses X-rays and computer processing to create detailed cross-sectional images of the body’s internal structures, including soft tissues, bones, and blood vessels. This imaging procedure is commonly used to diagnose injuries, detect tumors or internal bleeding, and monitor treatment effectiveness. Medicare typically pays for a CT scan, but coverage and patient financial responsibility depend on the type of Medicare and the setting where the scan is performed.
The Primary Coverage Source for Diagnostic Imaging
Original Medicare Part B is the primary source of coverage for diagnostic imaging like CT scans, as these procedures are most often performed on an outpatient basis. Part B, which is medical insurance, covers medically necessary services received outside of a formal inpatient hospital stay. Part B covers diagnostic tests provided in various outpatient settings, such as a doctor’s office, a free-standing imaging center, or a hospital outpatient department.
The CT scan must be deemed “medically necessary” for Part B coverage. This means a physician must order the test to diagnose or treat a specific disease, injury, or symptom. If the CT scan is performed during a qualifying inpatient stay, coverage falls under Original Medicare Part A (hospital insurance). However, the majority of CT scans are covered through Part B as a diagnostic outpatient service.
Coverage Conditions and Requirements
For a CT scan to be covered, it must meet the definition of “medical necessity,” a foundational requirement across all Medicare parts. Medically necessary services are those considered reasonable and appropriate for the diagnosis or treatment of a patient’s condition, meeting accepted standards of medical practice.
A Medicare-approved physician must formally order the CT scan to establish this necessity. The facility performing the scan must also be a Medicare-participating provider that accepts assignment. If the CT scan is performed while the patient is formally admitted as an inpatient, Part A rules apply, and the cost is typically bundled into the overall hospital stay charges. For an outpatient scan, Part B rules govern the coverage, which is the most common scenario for diagnostic imaging.
Understanding Your Out-of-Pocket Costs
Once a CT scan is determined to be medically necessary and covered by Original Medicare Part B, the patient is responsible for certain out-of-pocket costs. The annual Part B deductible must first be met before coverage begins. After the deductible is satisfied, the patient is generally responsible for a 20% coinsurance of the Medicare-approved amount for the CT scan.
If the outpatient scan takes place in a hospital’s outpatient department, the patient may also be charged a facility copayment in addition to the 20% coinsurance. For scans performed during a Part A inpatient stay, the patient is responsible for the Part A deductible per benefit period. Beneficiaries who have a Medigap (Medicare Supplement) plan may have their out-of-pocket costs, such as the Part B coinsurance, covered depending on the specific plan they have purchased.
Coverage Through Medicare Advantage
Individuals enrolled in a Medicare Advantage (MA) plan, also known as Medicare Part C, receive their benefits through a private insurance company that contracts with Medicare. These plans must cover all services included in Original Medicare (Parts A and B), meaning medically necessary CT scans are always covered. However, the specific financial structure and rules can differ significantly from Original Medicare.
Unlike the standard 20% coinsurance under Part B, MA plans set their own patient cost-sharing, which can involve varying copayments or deductibles for a CT scan. Many MA plans require beneficiaries to use providers within a specific network (HMO or PPO) and often mandate prior authorization. Patients should consult their specific plan documents to understand their financial responsibilities and procedural requirements.