Medicare Part B is the medical insurance half of Original Medicare, covering two broad categories: medically necessary services and preventive care. It pays for doctor visits, outpatient procedures, lab tests, mental health care, medical equipment, and a long list of preventive screenings at no cost to you. For 2025, the standard monthly premium is $185 with a $257 annual deductible. After you meet that deductible, you typically pay 20% of the Medicare-approved amount for most services.
Preventive Services at No Cost
One of the most valuable parts of Part B is its preventive care coverage. You pay nothing for most preventive services as long as your provider accepts Medicare assignment. This includes a one-time “Welcome to Medicare” preventive visit when you first enroll, plus a yearly wellness visit every year after that. These visits are designed to catch health problems early, when they’re easier and less expensive to treat.
The list of covered screenings is extensive. It includes mammograms, colonoscopies and other colorectal cancer screenings, lung cancer screenings, prostate cancer screenings, cervical and vaginal cancer screenings, cardiovascular disease screenings, diabetes screenings, glaucoma tests, bone density measurements, and hepatitis B and C screenings. Part B also covers HIV screenings and even pays for HIV prevention medication for people at risk.
Beyond cancer and disease detection, Part B covers depression screenings (one per year at a primary care office), alcohol misuse screenings and counseling, tobacco cessation counseling, obesity behavioral therapy, diabetes self-management training, and medical nutrition therapy. Four vaccines are covered under Part B at no cost: flu shots, pneumococcal shots, COVID-19 vaccines, and hepatitis B shots for eligible individuals.
Doctor Visits and Outpatient Care
Part B covers visits to doctors and specialists for diagnosing and treating medical conditions. This includes office visits, outpatient hospital services, lab tests, X-rays, and surgeries performed in an outpatient setting. After your annual deductible, you pay 20% of the Medicare-approved amount.
If a doctor recommends non-emergency surgery, Part B also covers a second surgical opinion, and if the second doctor disagrees with the first, it covers a third opinion too. Any additional tests the second or third doctor orders as part of that evaluation are also covered.
Mental Health Care
Part B covers outpatient mental health services, including individual and group psychotherapy with doctors or other licensed mental health professionals. Your yearly depression screening is free. For ongoing treatment, you pay 20% of the Medicare-approved amount after your deductible. If you receive mental health care in a hospital outpatient department rather than a private office, you may owe an additional copayment to the hospital. Part B also covers partial hospitalization programs for more intensive mental health treatment that doesn’t require a full inpatient stay.
Durable Medical Equipment
Part B covers medically necessary durable medical equipment (DME) prescribed by your doctor for use at home. To qualify, equipment must be reusable, serve a medical purpose, be primarily useful to someone who is sick or injured, and be expected to last at least three years.
Covered items include wheelchairs and scooters, walkers, canes, crutches, hospital beds, oxygen equipment and accessories, CPAP machines for sleep apnea, glucose monitors with test strips and supplies, infusion pumps, and commode chairs. After your deductible, you pay 20% of the Medicare-approved amount.
Home Health Services
If you’re homebound and need skilled medical care, Part B covers home health services at no cost to you. “Homebound” means leaving your home isn’t recommended because of your condition, or doing so requires considerable effort, special transportation, or help from another person. A healthcare provider must assess you face-to-face and certify that you need these services, and the care must come from a Medicare-certified home health agency.
Covered services include part-time skilled nursing care (wound care, IV therapy, injections, monitoring of serious illness), physical therapy, occupational therapy, and speech-language pathology. In most cases, you can receive up to 8 hours per day of combined skilled nursing and home health aide services, with a maximum of 28 hours per week. For short periods, that cap can increase to 35 hours per week if your provider determines it’s necessary.
Prescription Drugs Under Part B
Part B doesn’t replace a Part D drug plan, but it does cover a specific category of medications: drugs you wouldn’t normally give yourself at home. This mainly means injections and infusions administered in a doctor’s office or outpatient setting.
Beyond that, Part B covers several other drug categories. These include drugs used with durable medical equipment (like medication delivered through a nebulizer or infusion pump), injectable osteoporosis drugs, certain oral cancer drugs when an injectable version also exists, allergy treatments prepared by a doctor, immunosuppressive drugs after a Medicare-covered organ transplant, IV immune globulin for primary immune deficiency, blood clotting factors for hemophilia, and tube feeding or IV nutrition when you can’t absorb food normally. The four Part B vaccines (flu, pneumococcal, COVID-19, hepatitis B) also fall under this drug coverage.
Chronic Care Management
If you have two or more serious chronic conditions, Part B covers a monthly chronic care management service. This includes a comprehensive care plan listing your health problems, goals, medications, and providers. It also gives you 24/7 access to a care team for urgent needs, support during transitions between healthcare settings (like moving from a hospital to a rehab facility), medication reviews, and coordination of other chronic care needs.
Ambulance Services
Part B covers ground ambulance transportation when traveling any other way would endanger your health and you need to reach a hospital, critical access hospital, rural emergency hospital, or skilled nursing facility. Air ambulance (helicopter or airplane) is covered when you need immediate transport that ground vehicles can’t provide quickly enough. In both cases, Medicare only pays for transportation to the nearest appropriate facility. Non-emergency ambulance rides can also be covered if your doctor provides a written order confirming medical necessity.
What Part B Does Not Cover
Several common healthcare needs fall outside Part B. Routine dental care, including cleanings, fillings, extractions, and dentures, is not covered. Eye exams for prescription glasses and hearing exams for fitting hearing aids are excluded, along with the glasses and hearing aids themselves. Part B also does not cover long-term care, cosmetic surgery, massage therapy, routine physical exams (distinct from the covered annual wellness visit), or services from doctors who have opted out of Medicare. For dental, vision, and hearing coverage, many people add a Medicare Advantage plan or a standalone supplemental policy.