What Part B Medicare Covers: Doctor Visits, Tests, and Outpatient Care

Part B covers doctor visits, lab tests, imaging, and outpatient hospital services

Part B is the medical insurance piece of Original Medicare. It pays for services from doctors, specialists, therapists, and hospital outpatient departments — but not hospital stays (that is Part A). Part B covers the visit itself, diagnostic tests ordered during that visit, and procedures done in an office or outpatient clinic. You pay a monthly premium for Part B, and then you also pay a share of each service through a deductible and coinsurance.

Part B does not cover everything a doctor might order. Routine eye exams, dental work, hearing aids, and most preventive screenings fall outside it. Understanding what is and is not covered matters because an uncovered service can cost hundreds of dollars out of pocket.

Key Takeaways

• Part B covers doctor office visits, specialist consultations, lab work, X-rays, ultrasounds, and most imaging tests ordered by a doctor.
• Part B pays for outpatient hospital services like emergency room visits, same-day surgery, and chemotherapy infusions, but not overnight hospital stays.
• Part B does not cover routine eye exams, dental care, hearing aids, most preventive screenings, or services from providers who do not accept Medicare.
• You pay a monthly premium for Part B, plus a yearly deductible, then coinsurance (usually 20 percent) on each covered service.
• Part B coverage begins the month you turn 65 or the month you become may be able to access for Medicare due to disability or end-stage renal disease.

Doctor visits and specialist consultations

Part B covers a visit to your primary care doctor or any specialist — cardiologist, orthopedist, neurologist, and so on — as long as the doctor accepts Medicare. The visit itself is covered, and so is any exam or basic test the doctor does in the office, such as blood pressure checks or an EKG. If the doctor refers you to a specialist, that specialist visit is also covered under Part B.

You do not need a referral from your primary care doctor to see a specialist under Original Medicare. You can call any Medicare-accepting specialist directly and schedule an appointment. However, if you are in a Medicare Advantage plan (Part C), your plan may require a referral and may limit which specialists you can see.

The cost to you depends on whether you have met your yearly deductible. Once you have paid the deductible (which varies by year), you typically pay 20 percent coinsurance on the doctor's fee. If the doctor does not accept Medicare assignment, you may owe more.

Lab tests, imaging, and diagnostic procedures

Part B covers lab work ordered by a doctor — blood tests, urinalysis, and cultures. It also covers imaging ordered during or after a visit: X-rays, ultrasounds, CT scans, MRI scans, and PET scans. These services are covered whether they happen in a doctor's office, an outpatient imaging center, or a hospital outpatient department.

Screening tests — tests done to check for disease before you have symptoms — have different rules. Part B covers certain preventive screenings at no cost to you, such as colorectal cancer screening, mammograms, and bone density scans, if you meet age and risk requirements. However, if a screening finds something abnormal and the doctor orders a follow-up test to diagnose the problem, that follow-up test is covered under the standard Part B rules (deductible and coinsurance explore).

Routine eye exams and hearing tests are not covered by Part B. Neither are routine dental X-rays or cleanings. If you need these services, you must pay out of pocket or purchase a separate vision, dental, or hearing plan.

Outpatient hospital services and emergency care

Part B covers services provided in a hospital outpatient department, even if you do not spend the night. This includes emergency room visits, same-day surgery, infusions (such as chemotherapy or IV antibiotics), dialysis, and rehabilitation therapy. The hospital bills these as outpatient services, and Part B pays its share.

If you go to the emergency room and are admitted to the hospital for an overnight stay, Part A (hospital insurance) takes over. Part B stops paying for the room and board, though Part A does. If you are treated in the emergency room and sent home the same day, Part B covers that visit.

Observation status is a gray area. Sometimes a hospital keeps you overnight for monitoring but does not formally admit you — this is called observation. Observation stays are billed as outpatient services, so Part B covers them, but you pay coinsurance as if you were an outpatient. This can be confusing and expensive, so ask the hospital whether you are being admitted or placed in observation.

Therapy services and rehabilitation

Part B covers physical therapy, occupational therapy, and speech-language pathology when ordered by a doctor for a medical condition. These services are covered in an outpatient clinic, a hospital outpatient department, or your home (if a therapist visits you). Part B also covers mental health counseling and psychiatric services in an outpatient setting.

There are limits on how many therapy visits Part B will pay for in a year. These limits change, so check with Medicare or your doctor's office about the current cap. If you need more visits than the limit allows, you can pay out of pocket or explore whether your condition qualifies for an exception.

Therapy in a skilled nursing facility (a short-term care facility after a hospital stay) is covered by Part A, not Part B, as long as you were admitted to the hospital first and meet other requirements.

What Part B does not cover

Part B does not cover routine preventive care that is not on the covered screening list. Routine eye exams, eyeglasses, contact lenses, hearing aids, and routine dental care are not covered. Cosmetic surgery is not covered unless it is medically necessary to repair an injury or birth defect. Experimental treatments and drugs not yet approved by the FDA are not covered.

Part B does not cover services from providers who do not accept Medicare. If you see a provider who does not accept Medicare and does not tell you in advance that Medicare will not pay, you may still owe the full bill. Always ask a new provider whether they accept Medicare before your appointment.

Part B also does not cover long-term care, custodial care (help with bathing, dressing, eating), or most prescription drugs. Prescription drugs are covered under Part D (a separate plan you must choose). Custodial care in a nursing home or at home is not covered by any part of Original Medicare.

How much you pay for Part B coverage

Part B has a monthly premium, a yearly deductible, and coinsurance on each service. The premium amount depends on your income — higher earners pay more. The deductible is the amount you must pay out of pocket before Part B starts paying. Once you have met the deductible, you typically pay 20 percent coinsurance on the Medicare-approved amount for each service.

If a provider does not accept Medicare assignment, you may owe more than 20 percent. Providers who accept assignment agree to charge only the Medicare-approved amount. Providers who do not accept assignment can charge up to 15 percent more than the approved amount (called "balance billing").

Some people with low income and limited resources may may have access to for programs that help pay Part B premiums and cost-sharing. These programs are called Medicaid (if you may have access to) or the Medicare Savings Programs. Your state Medicaid office or a local Area Agency on Aging can tell you whether you may have access to.

Frequently Asked Questions

Do I have to enroll in Part B, or is it optional?

Part B is optional, but if you do not enroll when you first become may be able to access, you may pay a penalty for the rest of your life. Most people enroll when they turn 65. If you are still working and have health insurance through your job, you may be able to delay Part B without penalty, but you must report this to Medicare.

What happens if I see a doctor who does not accept Medicare?

If a doctor does not accept Medicare, Medicare will not pay, and you will owe the full bill. Some doctors accept Medicare for some patients but not others. Always ask whether a doctor accepts Medicare before you schedule an appointment. If a doctor tells you in advance that they do not accept Medicare, you can choose whether to see them and pay out of pocket.

Does Part B cover prescription medications?

No. Part B does not cover prescription drugs taken at home. Prescription drug coverage is Part D, a separate plan you must choose and pay for. Drugs given to you in a doctor's office or hospital outpatient setting (such as an infusion) are covered by Part B.

Are preventive services covered at no cost under Part B?

Some are. Part B covers certain preventive screenings — such as mammograms, colorectal cancer screening, and bone density scans — at no cost if you meet age and risk requirements. However, if a screening finds something abnormal and the doctor orders a diagnostic test to follow up, you pay coinsurance on that follow-up test.

What is the difference between Part B and a Medigap plan?

Part B is the government insurance itself. A Medigap plan is a private insurance policy that pays some of the costs Part B does not cover — such as coinsurance and deductibles. Medigap is optional but can lower your out-of-pocket costs. You cannot have both Medigap and Medicare Advantage (Part C) at the same time.