Medicare preventive care resource center
Medicare Preventive vs. Diagnostic Coverage
A screening, vaccine or wellness visit can be covered differently from diagnostic follow-up. Learn what changes the billing path and what to ask before an appointment.
The core distinction
Why the same test can follow two cost paths
Preventive or screening
The service looks for disease or risk before signs or symptoms are present and follows Medicare’s eligibility and frequency rules. Many covered preventive services have no patient cost when the provider accepts assignment.
Diagnostic
The service evaluates a symptom, known condition, prior abnormality or treatment response. The Part B deductible and usually 20% coinsurance can apply.
The claim diagnosis, service code, timing and medical record help determine how Medicare processes the claim. A scheduling label such as “annual exam” does not override Medicare’s benefit definitions.
Common situations
Where Preventive and Diagnostic Rules Often Change
More Than One Service at a Visit
A provider can furnish a covered preventive service and separately evaluate a new symptom, change treatment for a chronic condition or order diagnostic testing. The preventive portion can remain no-cost while the additional evaluation or test produces deductible or coinsurance.
Ask two separate questions: “Is this specific service covered as preventive for me now?” and “Could anything else planned or performed today be billed separately?” The office can explain expected coding, but Medicare or the plan makes the final claim decision.
Welcome and Wellness Visits
The Welcome to Medicare preventive visit is available once during the first 12 months of Part B. After that, a yearly wellness visit creates or updates a personalized prevention plan. Neither benefit is a comprehensive head-to-toe physical.
When the provider accepts assignment, the defined preventive visit has no deductible or coinsurance. Extra tests or services that are not part of the benefit can create costs.
Vaccines
Part B covers flu, COVID-19, pneumococcal and certain hepatitis B vaccinations. Part D generally handles other commercially available preventive vaccines, including shingles, RSV and Tdap. Adult vaccines recommended by the Advisory Committee on Immunization Practices are available through Part D without out-of-pocket cost when coverage requirements are met.
Follow-Up After an Abnormal Result
A screening mammogram can have no patient cost when Medicare’s rules are met, while a diagnostic mammogram generally has the Part B deductible and 20% coinsurance. Colonoscopy has special rules: a follow-up colonoscopy after a positive Medicare-covered noninvasive colorectal screening test is treated as a screening test, while removal of a polyp or other tissue during a screening colonoscopy can produce 15% coinsurance.
Before care
A five-question coverage check
- What is the purpose? Screening without symptoms, or evaluation of a symptom, abnormal result or known condition?
- Am I eligible now? Age, risk, frequency and time since the last service can matter.
- Does the provider accept assignment? That is often required for the preventive service to be no-cost under Original Medicare.
- Could additional work be billed? Ask about the office visit, pathology, anesthesia, facility, imaging and laboratory components.
- What does my plan require? Medicare Advantage can use network and prior-authorization rules while covering at least the Medicare preventive benefit.
Frequently asked questions
Preventive or Diagnostic? Questions
Are all Medicare preventive services free?
No. Many covered services have no cost when eligibility, timing and assignment requirements are met, but rules differ by service and related diagnostic work can be billed separately.
Does Medicare cover an annual physical?
Medicare covers a Welcome to Medicare preventive visit and yearly wellness visits under defined rules. Neither is a comprehensive routine physical.
Why did I owe money after a screening?
Possible reasons include diagnostic follow-up, removal or treatment during the procedure, a separate office service, frequency limits, provider assignment or a service that Medicare does not classify as preventive.
Do Medicare Advantage plans cover the same preventive services?
They must cover Medicare-covered preventive services, but network, referral, authorization and cost rules for related diagnostic services can differ by plan.
Can the provider guarantee how Medicare will process the claim?
The provider can explain intended coding and expected coverage, but Medicare or the plan makes the final claim determination.
Primary references
Official Sources
- Medicare.gov: Preventive and screening services
- Medicare.gov: Welcome to Medicare visit
- Medicare.gov: Yearly wellness visits
- Medicare.gov: Mammograms
- Medicare.gov: Colonoscopies
Reviewed against official sources on August 22, 2026. Medicare and state program rules can change; verify current requirements before acting.
Independent Medicare guidance
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