What Is Medicare Part B?

Let’s break it down together - because if you’re trying to understand what Medicare Part B actually covers (and doesn’t), you’re not alone.

We’ve helped thousands of folks through this, and we know how confusing it can be at first.

Medicare Part B is your medical insurance - it’s what helps pay for care outside the hospital. Doctor visits, outpatient procedures, lab work, durable medical equipment, and preventive care - that’s all Part B.

If Medicare Part A is your “hospital bed,” Part B is your doctor’s office, your blood test, your knee injection, or your annual checkup.

You’ll pay a monthly premium for Part B (more on that below), and it works with deductibles and coinsurance - meaning you’ll generally pay 20% of the cost of covered services after your deductible is met.

What Is Medicare Part B?

Medicare Part B is one of the two main parts of Original Medicare - the other is Part A.

If Part A covers your hospital room, then Part B covers everything the doctor does - whether you’re in a doctor’s office, at a clinic, or even inside the hospital.

Think of Part B as your day-to-day medical insurance.

It helps pay for:

• Doctor visits (primary care and specialists)
  
• Outpatient surgeries and procedures
  
• Preventive screenings (like mammograms and colonoscopies)
  
• Lab tests and X-rays
  
• Cancer treatments like chemotherapy and radiation
  
• Durable medical equipment (like walkers, wheelchairs, and oxygen)
  
• Mental health services
  
• ER visits if you're not admitted
  

One rule we often use with clients: “Part A = the bed. Part B = the people and services around the bed.”

So even if you're in the hospital, your doctor’s time, your labs, or your imaging tests are often billed through Part B - not Part A. That surprises a lot of people.

Bottom Line: if you want access to doctors, specialists, and the medical care that actually treats you, you need Part B. It plays a much bigger role than most people realize - especially when something serious comes up.

What Does Medicare Part B Cover?

Medicare Part B covers the kind of care you’re most likely to use day-to-day.

This includes doctor visits, outpatient tests and treatments, and the services that help you stay well or recover when something’s wrong.

Here’s a simple breakdown of what’s included.

#1. Doctor Visits

This includes your regular checkups, visits to specialists, follow-up care, and even things like second opinions.

If you’re seeing a cardiologist for your heart, a dermatologist for your skin, or just your family doctor - that’s all covered under Part B.

#2. Preventive Care

One of the things we always encourage people to take advantage of is Medicare’s preventive coverage.

Things like mammograms, colonoscopies, prostate screenings, flu shots, and annual wellness visits are often covered in full - no deductible, no copay.

It’s a great way to catch problems early or avoid them altogether.

#3. Outpatient Services

If you’re having a procedure done at a surgery center, getting a mental health evaluation, or going to physical therapy after an injury - that’s all considered outpatient care and falls under Part B.

Even emergency room visits (as long as you’re not admitted) are typically billed through Part B.

#4. Lab Work and Diagnostic Testing

Blood tests, urinalysis, MRIs, CT scans, ultrasounds - all those things your doctor orders to figure out what’s going on are included here.

#5. Durable Medical Equipment (DME)

If you ever need a wheelchair, a walker, oxygen equipment, or a CPAP machine, Medicare Part B helps pay for that too - as long as your doctor says it’s medically necessary.

#6. Serious Treatments Like Chemo or Dialysis

This surprises a lot of folks, but yes - chemotherapy, radiation, dialysis, and even infusion medications administered at a clinic are all covered under Part B.

These can be incredibly expensive without insurance, so it’s a big deal to have this coverage in place.

How Much Does Part B Cost?

Let’s talk numbers - because while Medicare Part B offers great coverage, it’s not free. There are a few different costs to keep in mind.

Monthly Premium

Most people in 2025 will pay $185 per month for Part B. This amount is set by Medicare and comes right out of your Social Security check if you’re already receiving benefits.

Now, if you’re a higher-income earner, you might pay more. This is called IRMAA - short for Income-Related Monthly Adjustment Amount.

If your income is above a certain threshold (based on your tax return from two years ago), your premium will be higher. Medicare sends a notice if this applies to you.

Annual Deductible

In 2025, you’ll pay a $257 annual deductible before Medicare starts paying its share. This is a once-a-year cost - not per service or per visit.

20% Coinsurance

After you meet that $257 deductible, you’ll generally pay 20% of the Medicare-approved amount for most services covered by Part B.

And here’s the part that surprises a lot of people: there’s no cap on how much that 20% can add up to.

If you have a long illness, need frequent treatments, or go through something like chemotherapy, those bills can grow quickly.

How to Protect Yourself From Big Bills

This is exactly why so many people choose to add either a Medicare Supplement (Medigap) plan or a Medicare Advantage plan.

These options help limit or even eliminate your out-of-pocket exposure under Part B.

We’ve worked with plenty of clients who didn’t realize how exposed they were until a major medical issue hit - having that extra layer of protection makes all the difference.

Who Is Eligible for Medicare Part B?

Most people become eligible for Medicare Part B when they turn 65 - but that’s not the only way to qualify.

Here’s how it works.

Standard Eligibility at Age 65

If you’re a U.S. citizen or a permanent legal resident who’s lived here for at least 5 continuous years, you’re eligible for Medicare when you turn 65.

And if you’ve worked and paid Medicare taxes for 10 years, you’ll likely get Part A premium-free - and you’ll have the option to sign up for Part B.

In most cases, if you're eligible for Part A, you're also eligible for Part B.

You can choose to enroll in both, or delay Part B if you have other coverage (like through an employer).

Eligibility Before 65

You can also get Medicare (including Part B) before age 65 if:

• You’ve been receiving Social Security Disability Insurance (SSDI) for 24 consecutive months
  
• You have End-Stage Renal Disease (ESRD) and need dialysis or a transplant
  
• You’ve been diagnosed with ALS (Lou Gehrig’s disease) - in this case, Medicare starts the same month your disability benefits begin
  

It’s important to note: if you're under 65 and qualify due to disability, you’ll be enrolled in Part A and Part B automatically - you don’t need to apply separately.

When Should You Enroll in Medicare Part B?

This is one of the most common (and most important) questions we hear - because getting the timing wrong can cost you for years.

Here's how we break it down for our clients.

If You’re Retiring at 65 (or Not Working)

You should enroll in Medicare Part B during your Initial Enrollment Period (IEP).

That’s a 7-month window that starts:

• 3 months before your 65th birthday
  
• Includes your birthday month
  
• Ends 3 months after
  

We always recommend enrolling as early as possible in that window to make sure your coverage starts on time.

If You’re Still Working at 65

This is where things get trickier. You may be able to delay Part B without a penalty if:

• You have employer coverage through a job (yours or your spouse’s), and
  
• That coverage is considered creditable (as good as or better than Medicare)
  

If that’s the case, you can wait to enroll in Part B until you retire or lose that employer coverage - and then sign up during a Special Enrollment Period without penalty.

One thing we always warn people about: COBRA, retiree coverage, or Marketplace plans usually don’t count as creditable coverage for delaying Part B.

That’s where a lot of folks get tripped up.

What If You Miss the Window?

If you don’t sign up for Part B when you’re first eligible - and you don’t have creditable coverage - you could face a 10% penalty for every 12-month period you delayed.

That penalty gets added to your Part B premium for life.

We’ve seen people end up paying hundreds more per year just because they waited too long or didn’t realize their employer plan didn’t qualify.

Bottom Line

If you’re new to Medicare, here’s what we want you to remember: Part B is essential.

It’s what covers the care you actually use - doctor visits, lab work, preventive screenings, outpatient procedures, and serious treatments like chemo or dialysis.

Yes, it comes with a monthly premium and some out-of-pocket costs. But skipping it or delaying it without understanding the rules? That’s when we see people get hit with lifetime penalties or wind up with no coverage when they need it most.

Before you make any final decisions about whether to enroll, delay, or coordinate with an employer plan - talk to someone who knows how this all plays out in real life.

We’ve helped hundreds of people through this process, and we’re happy to help you sort it out too.

Medicare Part B FAQs

Can I have Part B without Part A?

Not usually. You typically need to enroll in Part A before signing up for Part B - they go hand-in-hand as part of Original Medicare.

Does Part B cover prescriptions?

No, not most of them. Part B covers a few drugs given in a clinic or doctor’s office (like infusions), but for regular prescriptions you take at home, you’ll need a Part D drug plan.

What if I’m still working at 65?

You may be able to delay Part B without a penalty if you have creditable coverage through your job or your spouse’s job. But it depends - check with an expert to be sure.

What’s the difference between Part B and a Medicare Advantage plan?

Part B is part of Original Medicare, run by the government. A Medicare Advantage plan is run by a private insurance company and includes Part B coverage - but usually with copays, provider networks, and prior authorizations. They work very differently.

How do I pay for Part B if I’m not on Social Security yet?

Medicare will send you a bill every 3 months. Once you start taking Social Security, your Part B premium will be automatically deducted.

Texas Medicare Resources

If you’re in Texas, here are some trusted sources:

• Texas SHIP – The State Health Insurance Assistance Program offers free, unbiased Medicare help from trained counselors
  
• Social Security Offices in Texas – To apply for Part B or ask questions, you can visit your local SSA office. Find your nearest location at www.ssa.gov/locator
  
• Texas Medicare Advantage and Medigap Options – We can help you compare local plans and providers that work with Part B, including Blue Cross, Mutual of Omaha, Aetna, and others.