Diagnostic mammograms are covered by most insurance plans, but unlike routine screening mammograms, they often come with out-of-pocket costs. The difference matters: screening mammograms are free under federal law for most insured women, while diagnostic mammograms are typically subject to your deductible, copay, or coinsurance. However, a growing number of states have passed laws eliminating those costs, and recent federal guideline updates are narrowing the gap.
How Diagnostic and Screening Mammograms Are Covered Differently
The Affordable Care Act requires most private insurance plans to cover preventive screening mammograms with zero cost sharing. That means no copay, no coinsurance, and no deductible. This applies to women at average risk starting between ages 40 and 50, with screening recommended at least every two years and up to annually.
A diagnostic mammogram is a different category. It’s ordered when something specific needs investigation: a lump you or your doctor found, breast pain, an abnormal screening result, or monitoring after a previous breast cancer diagnosis. Because it’s classified as a diagnostic service rather than a preventive one, most insurance plans treat it like any other medical test. That means it goes through your deductible first, and then you pay your plan’s coinsurance or copay on top of that.
This distinction creates a frustrating gap. A woman can walk in for a free screening mammogram, have the radiologist spot something unusual, and then owe money for the follow-up diagnostic imaging done the same day or shortly after. The average out-of-pocket cost for a diagnostic mammogram reached about $145 in 2023, up from roughly $84 in 2018 and 2019, according to data from the American Cancer Society Cancer Action Network. When biopsies or additional imaging are added, total follow-up costs can climb significantly higher.
A Key Update to Federal Guidelines
Federal women’s preventive services guidelines now recognize that screening doesn’t always end with a single mammogram. The updated recommendations state that when additional imaging is needed to complete the screening process, including follow-up mammograms, ultrasounds, or MRIs prompted by findings on the initial screen, those services are also considered part of screening. This means your insurance plan may be required to cover certain follow-up imaging at no cost if it’s directly tied to completing your screening evaluation rather than investigating a separate clinical concern.
The practical impact depends on how your insurer interprets and applies these guidelines. Some plans have already updated their policies; others lag behind. If you’re told a follow-up to an abnormal screening will cost you, it’s worth calling your insurer and asking whether the service qualifies as completion of screening under current preventive services guidelines.
State Laws That Eliminate Your Costs
More than two dozen states have passed laws requiring private insurers to cover diagnostic breast imaging with no out-of-pocket costs. These laws typically cover diagnostic mammograms, breast ultrasounds, and breast MRIs when ordered by a healthcare provider. As of early 2025, states with these protections in place or taking effect soon include New York, Connecticut, Louisiana, Tennessee, Montana, Washington, Maine, Maryland, Minnesota, Mississippi, Missouri, Nevada, New Mexico, Oregon, Colorado, Arkansas, Kentucky, New Hampshire, Oklahoma, Alaska, Illinois, Massachusetts, Vermont, Virginia, Wisconsin, Alabama, and Pennsylvania. Effective dates vary by state, with the earliest laws active since 2017 and the latest not taking effect until 2027.
These state laws generally apply to private insurance plans regulated by the state, which covers most employer plans purchased through the open market and ACA marketplace plans. Large employers that self-insure (meaning they pay claims directly rather than buying a policy from an insurer) are regulated under federal law instead and aren’t bound by state mandates. If you’re unsure which type of plan you have, your HR department or the back of your insurance card can point you in the right direction.
One common exception: if applying zero cost sharing would disqualify a high-deductible health plan from eligibility for a health savings account under federal tax rules, the state law may not apply to that plan.
Medicare Coverage
Medicare Part B covers diagnostic mammograms when they’re medically necessary, with no limit on frequency. You can get more than one per year if your doctor determines it’s needed. After you meet the annual Part B deductible, you pay 20% of the Medicare-approved amount for each diagnostic mammogram. Screening mammograms under Medicare, by contrast, are covered once every 12 months at no cost.
Medicaid Coverage
Medicaid coverage for diagnostic mammograms varies by state. Women who qualify for Medicaid through their state’s ACA expansion are entitled to the same preventive screening benefits as those with private insurance. For people enrolled in traditional Medicaid (not through expansion), breast cancer screening and related services are technically classified as optional benefits, and each state sets its own scope of coverage. In practice, most state Medicaid programs do cover breast cancer screening and diagnostic services, but the specifics of what’s included and any cost sharing depend on where you live.
Why Billing Codes Matter
The single biggest factor in what you owe is how your mammogram gets coded on the claim submitted to your insurer. Screening and diagnostic mammograms use different billing codes, and that code determines whether your plan treats the service as free preventive care or as a standard medical claim subject to cost sharing.
Sometimes a mammogram that starts as a screening gets recoded to diagnostic during the same visit. This can happen if the radiologist sees something that requires additional views right away. When that occurs, the entire visit may be billed as diagnostic, which shifts the cost to you. If you receive a surprise bill after what you thought was a routine screening, ask the imaging facility which billing code was used and whether any portion qualifies as screening. Coding errors do happen, and they’re worth questioning.
If You’re Uninsured or Underinsured
The CDC’s National Breast and Cervical Cancer Early Detection Program provides free or low-cost breast cancer screening and diagnostic services to women with low incomes who lack adequate insurance. You may qualify if your income is at or below 250% of the federal poverty level, you’re between ages 40 and 64, and you have no insurance or insurance that doesn’t cover these exams. The program covers both screening and diagnostic services, including follow-up after an abnormal result. Each state runs its own version of the program, and you can find your local program through the CDC’s website.
Many imaging centers and hospitals also offer financial assistance programs or sliding-scale pricing. If you’re facing a diagnostic mammogram without coverage, call the facility’s billing department before your appointment to ask about reduced rates or payment plans. Costs for uninsured patients paying out of pocket can range widely depending on the facility and your location, but negotiated cash prices are often significantly lower than the amount billed to insurance.