Medicare Part B: Doctor Visits, Outpatient Care and Prevention

If Part A is Medicare's hospital coverage, Part B is the coverage you use most often. It pays for doctor visits, outpatient care, lab work, medical equipment and a long list of preventive services.

Part B also has a monthly premium and its own deductible. What you pay depends partly on whether your doctor "accepts assignment." This guide covers what Part B includes, how its costs work under Original Medicare, and the details that cause the most confusion.

This is general information, not insurance, tax or medical advice, and this independent site isn't connected with Medicare or CMS. If you're in a Medicare Advantage Plan, your plan must cover the same Part B services, but your costs and rules may be different. For personal help, contact your State Health Insurance Assistance Program (SHIP) or call 1-800-MEDICARE (1-800-633-4227).

What Part B covers

Medicare.gov describes two broad types of Part B services:

• Medically necessary services: services or supplies that meet accepted standards of medical practice to diagnose or treat your condition
• Preventive services: care to prevent illness or catch it early, when treatment is likely to work best

In everyday terms, the Medicare & You 2027 handbook says Part B helps cover doctors' services, outpatient care, some home health services, durable medical equipment, mental health services, limited outpatient prescription drugs and other medical services. Medicare.gov's Part B page also lists ambulance services, clinical research, oxygen equipment and substance use disorder care.

Ambulance coverage has conditions. The handbook says Medicare covers ground ambulance transportation for medically necessary services when traveling in any other vehicle could endanger your health. Non-emergency ambulance rides are covered only in some cases, with a doctor's written order.

If you're not sure whether something is covered, Medicare.gov has a coverage lookup tool, and 1-800-MEDICARE can tell you.

Preventive visits and screenings

Prevention is one of Part B's strongest features. Medicare.gov says you pay nothing for most preventive services if your provider accepts assignment. Two visits are worth knowing about:

• "Welcome to Medicare" preventive visit: According to the Medicare & You 2027 handbook, you can get this visit during your first 12 months with Part B. It reviews your medical and social history and covers education about screenings, vaccines and referrals.
• Yearly "Wellness" visit: The 2027 handbook says that after you've had Part B for more than 12 months, you can get this visit once every 12 months. It's used to create or update a personal prevention plan and includes a health risk questionnaire and a cognitive assessment.

Neither is a full physical exam, and that matters for your bill. The handbook warns that if your provider does extra tests or services during the visit that the preventive benefit doesn't cover, you may owe coinsurance and the Part B deductible may apply. If Medicare doesn't cover the extra service at all, such as a routine physical, you may owe the full amount. It's reasonable to ask the office ahead of time what will be billed.

Part B also covers flu, hepatitis B and pneumococcal vaccines. The handbook says most other recommended adult vaccines, such as shingles and RSV, are generally covered under Part D at no cost to you.

What Part B costs in 2026

For 2026, Medicare.gov lists these Original Medicare Part B costs:

• Premium: $202.90 a month in 2026, or higher depending on income. You pay it even in months you don't use any services.
• Deductible: $283 for 2026 before Original Medicare starts to pay.
• Coinsurance: usually 20% of the Medicare-approved amount for each covered service after the deductible, when your provider accepts assignment.
• Out-of-pocket limit: none, unless you have supplemental coverage such as Medigap or Medicaid, or you join a Medicare Advantage Plan.

The higher premium for people with higher incomes is called the Income-Related Monthly Adjustment Amount (IRMAA). The Medicare & You 2027 handbook says it's based on your modified adjusted gross income from 2 years earlier. Our Costs & Help Paying section covers IRMAA, late enrollment penalties and programs that help with premiums in detail.

If you get Social Security or Railroad Retirement Board benefits, the handbook says your Part B premium is deducted from your monthly payment. Otherwise, you'll get a bill.

One more cost to watch: outpatient care in a hospital. Medicare.gov's 2026 cost table says you usually pay 20% for the doctor's services plus a separate copayment to the hospital for each outpatient service. That means the same procedure can cost you more in a hospital outpatient department than in a doctor's office. In most cases, the copayment for a single outpatient service won't be more than the Part A hospital deductible.

Assignment: why your doctor's Medicare status matters

Assignment means your doctor or supplier agrees (or is required by law) to accept the Medicare-approved amount as full payment for covered services. According to the Medicare & You 2027 handbook, most providers accept assignment, but you should check. When they do, they can charge you only the Medicare deductible and coinsurance, and they must submit the claim to Medicare for you.

Providers who don't accept assignment for all services are called "non-participating." The handbook says they may ask you to pay the full charge at the time of service. The 2027 handbook also says they can charge more than the Medicare-approved amount, though in many cases no more than 15% above it. That cap is called the "limiting charge."

A third group has opted out of Medicare entirely. The handbook says Medicare won't pay for covered services from an opt-out provider except in an emergency or urgent situation. If you still want to see one, you and the provider sign a private contract and you pay what you agree to. Medicare.gov's care compare tool shows whether a provider accepts assignment, and CMS offers a separate lookup for opt-out providers.

Limited drug coverage under Part B

Part B is not a prescription drug plan. The Medicare & You 2027 handbook explains that Part B doesn't cover most drugs, with exceptions such as some drugs given by infusion or injection in a doctor's office, certain immunosuppressive drugs, and insulin used with a traditional pump. For insulin used with a Part B-covered pump, Medicare.gov's Part B page (as of October 2026) says your cost for a month's supply can't be more than $35, and the Part B deductible doesn't apply. For the drugs you pick up at a pharmacy, you need Part D or other drug coverage.

Keeping or delaying Part B

If you're enrolled automatically, the handbook says most people keep Part B. You can decline it before your coverage starts, but delaying can lead to a coverage gap and a late enrollment penalty that lasts as long as you have Part B, unless you have qualifying coverage from current employment. Check the rules for your situation before you decide. Our guide "Medicare With Job, VA or TRICARE Coverage: Who Pays First" explains how job-based coverage fits in.

Check your Medicare Summary Notice

With Original Medicare, you'll get a Medicare Summary Notice listing services billed to Medicare. The Medicare & You 2027 handbook notes it's not a bill. It shows what Medicare paid and what you may owe. Compare it with your own records. If you see services you didn't get, the handbook advises asking the provider for an itemized statement and calling 1-800-MEDICARE if something still looks wrong, because it can be a sign of fraud or medical identity theft.

Key takeaways

• Part B covers doctors' services, outpatient care, durable medical equipment, some home health care and many preventive services.
• For 2026, Medicare.gov lists a $202.90 standard monthly premium, a $283 yearly deductible and usually 20% coinsurance, with no out-of-pocket limit in Original Medicare alone.
• The "Welcome to Medicare" and yearly "Wellness" visits are free with providers who accept assignment, but they aren't routine physicals, and extra services may cost you.
• Providers who accept assignment cost you less. Non-participating providers can charge somewhat more, and opt-out providers aren't paid by Medicare.
• Part B covers only limited drugs. Most prescriptions need Part D or other drug coverage.

Sources

• Medicare.gov, What Part B covers
• Medicare.gov, Costs (2026 amounts)
• Centers for Medicare & Medicaid Services, Medicare & You 2027 (official U.S. government Medicare handbook)
• Centers for Medicare & Medicaid Services, 2026 Medicare Parts A & B Premiums and Deductibles (November 14, 2025)
• Medicare.gov, Parts of Medicare