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

Medicare Part B is the medical insurance portion of Medicare that pays for services you receive outside a hospital bed — mainly visits to doctors and specialists, diagnostic tests, imaging like X-rays and ultrasounds, and treatment at outpatient clinics. It does not cover hospital stays (that is Part A), prescription drugs (that is Part D), or long-term care. Part B requires a monthly premium, a yearly deductible, and coinsurance on most services.

Part B is optional, but most people who have Part A should enroll in Part B during their initial enrollment window. If you delay enrollment without a valid reason, you may face a permanent penalty on your premium. The coverage begins the month after you enroll, or on your 65th birthday if you enroll during your initial window.

Key Takeaways

  • Part B covers doctor office visits, specialist consultations, preventive screenings, lab work, imaging, and outpatient procedures — but not hospital inpatient stays or prescription drugs.
  • You pay a monthly premium (the standard amount in 2024 is $164.90, but varies by income), a yearly deductible ($240 in 2024), and typically 20 percent coinsurance after the deductible is met.
  • Preventive services like annual wellness visits, cancer screenings, and vaccines are covered at no cost to you after you meet the deductible for some services.
  • Delaying Part B enrollment after your initial window can result in a permanent 10 percent increase to your premium for each year you delay.
  • Part B does not cover routine dental, vision, hearing aids, or long-term care — you may need a separate plan or out-of-pocket payment for these.

Doctor visits and specialist care covered by Part B

Part B pays for visits to your primary care doctor, cardiologists, orthopedists, neurologists, and other specialists. The visit itself is covered, along with any routine examination or assessment the doctor performs during that visit. You pay 20 percent coinsurance after you have met your yearly deductible ($240 in 2024).

Telehealth visits with doctors are also covered under Part B, whether through your doctor's office, a clinic, or a telehealth provider. The coinsurance rules are the same as in-person visits. If your doctor orders tests or imaging during the visit, those are billed separately under Part B's diagnostic and imaging rules.

Diagnostic tests and lab work covered by Part B

Part B covers blood tests, urinalysis, and other laboratory work ordered by your doctor. It also covers diagnostic imaging such as X-rays, CT scans, MRI scans, and ultrasounds when medically necessary. Preventive screening tests — such as colorectal cancer screening, prostate cancer screening, and bone density scans — are covered at no cost to you, even before you meet your deductible, if your doctor orders them as part of routine preventive care.

Pathology services, where a lab analyzes tissue or fluid samples, are covered under Part B. If you have the test done at a hospital outpatient department, you may see a separate facility charge in addition to the test charge itself. Both are covered, but you will owe coinsurance on both.

Outpatient hospital services and procedures

Part B covers care you receive at a hospital outpatient department, such as emergency room visits that do not result in admission, same-day surgery, chemotherapy, dialysis, or rehabilitation therapy. You pay a copay or coinsurance depending on the service and the hospital's billing structure. Outpatient hospital services are distinct from inpatient stays, which are covered under Part A.

Ambulatory surgery centers — facilities that perform surgery on patients who go home the same day — are also covered under Part B. Mental health services, including therapy and psychiatric visits, are covered at the same 20 percent coinsurance rate as other doctor visits after you meet your deductible.

Preventive services with no cost-sharing

Medicare Part B covers a range of preventive services at no cost to you, meaning you do not pay a copay or coinsurance, even before you meet your yearly deductible. These include an annual wellness visit with your primary care doctor, colorectal cancer screening, mammograms, Pap tests, prostate cancer screening, bone density scans, diabetes screening, cardiovascular screening, and certain vaccines such as flu, pneumonia, and shingles.

To receive these services at no cost, your doctor must order them as preventive care — not as a treatment for a symptom or existing condition. If you come in with abdominal pain and your doctor orders a colonoscopy to investigate, that colonoscopy may be billed as diagnostic rather than preventive, and you may owe coinsurance. Ask your doctor in advance whether a screening is being ordered as preventive care.

What Part B does not cover

Part B does not cover hospital inpatient stays (covered by Part A), prescription drugs (covered by Part D), routine dental work, routine vision care or eyeglasses, hearing aids, long-term care in a nursing home or assisted living facility, or custodial care. It also does not cover most routine foot care, acupuncture, or cosmetic procedures.

Some services are covered only under specific circumstances. For example, physical therapy is covered if ordered by a doctor for a medical condition, but not for general fitness or wellness. Chiropractic care is limited to manual manipulation of the spine for subluxation, and only if ordered by a doctor. If you need services not covered by Part B, you may purchase supplemental insurance (Medigap) or enroll in a Medicare Advantage plan, which may offer additional coverage.

How much you pay: premiums, deductibles, and coinsurance

The standard Part B monthly premium in 2024 is $164.90, but the amount you pay depends on your income. If your modified adjusted gross income exceeds certain thresholds, you pay a higher premium through Income-Related Monthly Adjustment Amounts (IRMAA). The yearly deductible is $240 in 2024. After you meet the deductible, you typically pay 20 percent coinsurance on most services.

Some services, such as preventive care, have no cost-sharing. Others, such as mental health services in an outpatient setting, may have different cost-sharing rules. If you see a doctor who does not accept Medicare assignment, you may owe more than the standard coinsurance. Always ask your doctor's office whether they accept Medicare assignment before your visit.

Enrollment and when coverage begins

Your initial enrollment window for Part B is the seven-month period that includes three months before your 65th birthday, the month of your birthday, and three months after. If you enroll during this window, your coverage begins on the first day of the month in which you turn 65, or the first day of the month after you enroll, whichever is later.

If you miss your initial enrollment window and do not have other creditable coverage, you can still enroll during the General Enrollment Period (January 1 through March 31 each year), but your coverage will not begin until July 1 of that year. You will also pay a permanent 10 percent premium increase for each year you delayed enrollment. The only exceptions are if you were covered by an employer group health plan or had other creditable coverage; in those cases, you may enroll without penalty during an eight-month window after that coverage ends.

Frequently Asked Questions

Does Part B cover my annual physical exam?

Yes. Medicare Part B covers an annual wellness visit with your primary care doctor at no cost to you. This visit includes a health assessment, review of your medical history, and screening for certain conditions. If your doctor performs additional services beyond the wellness visit, those may be billed separately and subject to coinsurance.

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

If a doctor does not accept Medicare assignment, you may owe more than the standard 20 percent coinsurance. The doctor can charge up to 15 percent above Medicare's approved amount. Ask your doctor's office in advance whether they accept Medicare assignment to avoid surprise bills.

Are prescription drugs covered under Part B?

No. Prescription drugs are covered under Medicare Part D, a separate plan you must enroll in. Some drugs administered by a doctor in an office or clinic setting — such as chemotherapy or certain biologics — are covered under Part B, but oral medications you take at home are not.

Do I have to pay the Part B premium if I am still working?

Yes. If you are 65 or older, you must enroll in Part B and pay the premium, even if you are still working and have employer coverage. The exception is if your employer has 20 or more employees; in that case, you may delay Part B enrollment without penalty while you remain employed and covered by the employer plan.

Can I drop Part B if I do not think I need it?

You can drop Part B, but you will face a permanent 10 percent premium increase if you enroll later. The only time you can drop Part B without penalty is if you have other creditable coverage, such as an employer group health plan, and you enroll in Part B within eight months after that coverage ends.