Part B covers doctor visits, outpatient tests, and preventive care — but not hospital stays or prescription drugs
Part B is the medical insurance portion of Original Medicare. It pays for services you receive outside a hospital: visits to your doctor's office, lab tests, X-rays, physical therapy, ambulance transport, and preventive screenings. Part B does not cover hospital inpatient stays (that is Part A), prescription drugs (that is Part D), or long-term care.
Part B is optional, but most people who have Part A enroll in it. You pay a monthly premium for Part B, and then you pay a share of the cost when you use a covered service. The premium amount changes each year based on your income.
Part B covers the service itself — the doctor's time, the lab work, the equipment used — but you are responsible for your deductible and coinsurance. Understanding what Part B covers and what it does not helps you plan for out-of-pocket costs and know when to use it.
Key Takeaways
- Part B covers doctor office visits, lab tests, imaging (X-rays and ultrasounds), preventive care, and outpatient procedures, but you pay a deductible and coinsurance for most services.
- Part B does not cover hospital stays, prescription drugs, dental care, vision care, hearing aids, or long-term care — those require different coverage.
- You must enroll in Part B during your initial enrollment window or pay a late penalty for as long as you have Medicare.
- Part B premiums are deducted from your Social Security check each month, and the amount depends on your income from two years prior.
Doctor visits and office-based care Part B covers
Part B pays for visits to your primary care doctor, specialists, and other healthcare providers who accept Medicare. This includes the office visit itself, any tests or procedures done in the office, and time spent with nurses or physician assistants. You pay 20 percent coinsurance after you meet your annual deductible.
Part B also covers outpatient surgery and procedures — for example, cataract removal, colonoscopy, or a skin biopsy — when performed in a doctor's office or outpatient surgery center. The provider bills Medicare directly, and you pay your share of the cost. If a procedure requires hospitalization (overnight stay), it falls under Part A instead.
Mental health visits and substance use disorder treatment are covered the same way as other doctor visits. You pay your deductible and coinsurance, and there is no limit on the number of visits you can have.
Tests, imaging, and diagnostic services Part B covers
Part B covers lab tests ordered by your doctor — blood work, urinalysis, and other diagnostic tests performed in a lab or doctor's office. It also covers imaging services: X-rays, ultrasounds, CT scans, and MRI scans when medically necessary. You pay 20 percent coinsurance after your deductible.
Pathology services — the analysis of tissue samples or blood cultures — are covered under Part B. If you have a biopsy or blood test, the lab work itself and the interpretation by the pathologist are both covered.
Home health services, including skilled nursing care and physical therapy in your home, are covered under Part B when ordered by your doctor and deemed medically necessary. You typically pay nothing for home health services, but you may pay coinsurance for certain equipment or supplies.
Preventive care and screenings Part B covers
Part B covers a range of preventive services with no deductible or coinsurance: annual wellness visits, mammograms, colorectal cancer screenings, prostate cancer screenings, bone density tests, cardiovascular screenings, and diabetes screenings. You also receive one initial preventive physical exam when you first enroll in Part B.
Flu shots, pneumonia vaccines, and shingles vaccines are covered at no cost. Vaccines for other conditions — such as hepatitis B or tetanus — are covered if your doctor determines they are medically necessary for you.
Counseling services for depression, smoking cessation, and weight loss are covered preventive benefits. Your doctor must order them, and you pay nothing if the provider is in-network and accepts Medicare assignment.
What Part B does not cover
Part B does not cover hospital inpatient stays, emergency room visits, or skilled nursing facility care — those are Part A services. It does not cover prescription drugs, which require Part D coverage. Dental care, routine vision exams, eyeglasses, and hearing aids are not covered by any part of Original Medicare.
Cosmetic procedures are not covered, even if they have a medical component. Routine foot care, such as toenail trimming, is not covered unless you have diabetes or a related condition. Acupuncture, chiropractic care, and massage therapy are generally not covered, though acupuncture for chronic lower back pain may be covered in limited circumstances.
Long-term care in a nursing home or assisted living facility is not covered by Part B or any part of Original Medicare. Travel outside the United States is not covered, except in limited cases involving Canada or Mexico.
How you pay for Part B services
Part B has an annual deductible (the amount you pay out of pocket before Part B starts paying). Once you meet the deductible, you pay 20 percent coinsurance for most services. For some preventive services, you pay nothing.
Your Part B premium is deducted automatically from your Social Security check each month. The standard premium amount changes each year. If your income is above a certain threshold, you pay an additional surcharge called an Income-Related Monthly Adjustment Amount (IRMAA). The income used to calculate IRMAA is from two years prior, so changes to your income may not affect your premium when ready.
If you see a provider who does not accept Medicare assignment, you may pay more than the Medicare-approved amount. Providers who accept assignment agree to charge only what Medicare allows, and you pay your 20 percent coinsurance on that amount.
When to enroll in Part B and what happens if you miss the important date
You can enroll in Part B during your Initial Enrollment Period, which begins three months before the month you turn 65 and ends three months after. If you do not enroll during this window and you do not have other may have access to coverage, you will pay a late enrollment penalty for as long as you have Medicare.
The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but did not enroll. If you delayed enrollment because you had employer coverage, you may be able to enroll without penalty during a Special Enrollment Period.
If you are already receiving Social Security benefits when you turn 65, you are enrolled in Part B automatically. You have a chance to decline it, but if you do and later want to enroll, you will face the late penalty unless you have may have access to coverage.
Frequently Asked Questions
Does Part B cover my doctor's office visit if I have not met my deductible yet?
Yes, but you will pay the full cost of the visit until you meet your annual deductible. Once you meet it, you pay 20 percent coinsurance. Preventive services like annual wellness visits do not count toward your deductible and cost nothing.
If I have Part B, do I still need supplemental insurance?
Part B covers 80 percent of approved costs after your deductible, leaving you responsible for 20 percent coinsurance. Many people buy Medigap (supplemental) insurance to cover that coinsurance, or they enroll in a Medicare Advantage plan instead of Original Medicare. Neither is required, but both can reduce your out-of-pocket costs.
Does Part B cover telehealth visits with my doctor?
Yes. Telehealth visits are covered the same way as in-person visits — you pay your deductible and coinsurance. The provider must be enrolled in Medicare and accept Medicare patients for the visit to be covered.
What happens if I need a test but my doctor says it is not medically necessary?
Part B covers only services deemed medically necessary by your doctor and approved by Medicare. If Medicare denies a claim, you will receive a notice explaining why. You can request a review of the decision if you believe it was wrong.
Can I use Part B at any doctor or hospital?
Part B works with any doctor or provider who accepts Medicare, regardless of location within the United States. You do not need to choose a primary care doctor or get referrals, though your doctor may recommend seeing a specialist. Providers outside the U.S. are generally not covered.