Medicare Advantage HMO vs PPO: Networks and Referrals

Medicare Advantage HMO vs PPO is a question about where care is covered, and on what terms. An HMO is a Medicare Advantage plan. You generally must get care and services from doctors, other health care providers, and hospitals in that plan's network. The exceptions Medicare lists are emergency care, out-of-area urgent care, and temporary out-of-area dialysis. [1] In most HMOs you choose a primary care doctor, and in most cases you need a referral to see a specialist. [1] A PPO is also a Medicare Advantage plan with a network. You pay less when you stay in that network. [2] You can generally use out-of-network providers for covered services, if they participate in Medicare or accept assignment, but you usually pay more. [2] A PPO does not require a primary care doctor, and it does not require a referral to see a specialist. [2]

Those are national descriptions. They are not a North Carolina statute and they are not a Piedmont Triad directory. You generally must live in the service area of the plan you join, and you should ask your own doctors whether they are in that plan's network. [6] The rules for referrals, out-of-network costs, and prior authorization belong in the plan's Evidence of Coverage. [3][7]

Practical takeaways

• In an HMO, routine care generally stays in network. Other than the exceptions below, care outside the network may leave you paying the full cost. [1]
• Emergency care, out-of-area urgent care, and temporary out-of-area dialysis are covered under an HMO inside or outside the network. [1][5]
• Most HMOs ask you to choose a primary care doctor. In most cases a specialist visit needs a referral. Some services, such as a yearly mammogram screening, do not. [1]
• A PPO covers in-network care and, for covered services, out-of-network care. Out-of-network care usually costs more. Call the plan before that visit. [2]
• A PPO does not require a primary care doctor or a specialist referral. [2] Prior authorization is separate. Advantage plans typically use it for certain services, and the Evidence of Coverage is where those rules are written. [3][7]
• Private Fee-for-Service (PFFS) plans and Medical Savings Account (MSA) plans are other Medicare Advantage types. This article is not about them. [3][8]
• Match your doctors to the plan's directory. Networks can change during the year. There is no single statewide HMO-versus-PPO list. [5][6]

Both are Medicare Advantage, not Medigap

An HMO and a PPO are both types of Medicare Advantage Plan (Part C) offered by a private company. [1][2] A Medigap policy is different from a Medicare Advantage Plan: Medicare Advantage is another way to get your Medicare coverage besides Original Medicare, and Medigap supplements Original Medicare. You cannot use Medigap to pay a Medicare Advantage plan's copayments, deductibles, and premiums. [4]

The Centers for Medicare & Medicaid Services describes Part C as the program that contracts with organizations to offer coordinated care plans, including HMOs and PPOs, along with Medicare Medical Savings Account plans and private fee-for-service plans. Those plans provide Medicare Part A and Part B benefits. [8] For how an Advantage plan can bundle hospital, medical, and drug coverage, see our Medicare Advantage (MAPD) page.

The network is local, including in North Carolina

To join a Medicare health plan, you generally must live in the service area of the plan you want to join. [6] Medicare's joining steps start with finding which plans are available in your area, then asking your doctors whether they are in the plan's network. [6] In many cases you can only use doctors and other providers who are in the plan's network and service area for non-emergency care. Some plans offer non-emergency coverage out of network, but typically at a higher cost. [5]

That is why we do not talk about one North Carolina HMO rule or one North Carolina PPO rule. Medicare publishes the national pattern for each plan type. [1][2] The directory and the service area belong to the plan. A plan a friend joined in another county is not automatically a plan you can join, and a doctor who takes one Advantage plan has not agreed to take every Advantage plan. [5][6] Greensboro, High Point, Winston-Salem, and the counties around them can show different lists for different addresses. Look up the address where the person with Medicare lives, then open that plan's directory.

Networks move. A Medicare Advantage plan can add or remove providers at any time during the year, and a provider can leave at any time. [5] The plan must still protect you from interruptions in medical care and keep access to medically necessary covered benefits. [5] If your provider leaves, you need a new in-network provider for covered services. The plan should make a good faith effort to give at least 30 days' notice, and it will notify you if a provider you see regularly, such as your primary care provider, is leaving [5]. Confirm network status when you schedule, not only on enrollment day. [5]

If you live in another state for part of the year, Medicare says to check whether the plan will cover you there. [6] That check is about the contract in your hand, not a reason to treat either plan type as the one that always works better away from home.

What an HMO generally requires

When you have an HMO, you generally must get care and services from doctors, other health care providers, and hospitals in the plan's network, except emergency care, out-of-area urgent care, and temporary out-of-area dialysis. [1] Those three services are covered whether you get them in the network or outside it. [5] For other care, if you go outside the plan's network, you may have to pay the full cost. [1] A doctor who "accepts Medicare" is not automatically in this HMO. The network is the group of providers who have contracted with the plan. [5]

In most HMOs you need to choose a primary care doctor. [1][3] In some Medicare Advantage plans, that choice also selects the hospitals and specialty networks tied to that doctor. If you want a particular hospital or specialist, you may need a referral from the primary care doctor. [5] In most cases you have to get a referral to use a specialist. Certain services, like yearly mammogram screenings, do not. [1] The comparison chart's answer on HMO referrals is yes. [3] Specialty care is generally coordinated that way, except where the plan says a referral is not required. Read the list for the plan in front of you.

Some HMOs are Point-of-Service plans, often called HMOPOS. They may allow some services out of network for a higher copayment or coinsurance. [1][3] That is still an HMO. It is not a promise that every service works like a PPO. The out-of-network piece covers some services, at a higher cost, and only if you follow the plan's rules. [1] If your doctor leaves the plan, the plan will notify you, and you may choose another provider in the plan. [1] Follow the plan's rules, including prior approval when the plan requires it. [1]

What a PPO generally allows

A PPO has a network of doctors, other health care providers, and hospitals. [2] You pay less if you use providers and facilities in the network. [2] You can generally go to out-of-network providers for covered services, but you will usually pay more. [2][5] Those out-of-network providers need to participate in Medicare or accept assignment. [2] Before that visit, contact the PPO to make sure the services are medically necessary and covered. [2] You are always covered for emergency and urgent care. [2] The comparison chart matches this shape: the plan has a network you may use, and you may go outside it, but you may pay more. [3]

In a PPO you do not need to choose a primary care doctor, and you do not need a referral to see a specialist. [2][3] You still need a covered service, and an out-of-network provider still has to meet the rule above. "No referral" is not "no phone call." If the doctor is outside the network, contact the plan first. [2] Medicare also says that because certain providers are "preferred," you can save money by using the PPO network. [2] That compares in-network cost with out-of-network cost inside a PPO. It does not say a PPO is always cheaper than an HMO, and we will not say that either.

Other plan types, briefly

Medicare's comparison chart also lists Private Fee-for-Service plans, Special Needs Plans, and Medical Savings Account plans. [3] CMS places HMOs, PPOs, MSA plans, and PFFS plans in the same Part C family. [8] PFFS and MSA plans exist. They are not the subject of this post.

MSA plans generally do not have network providers. You can go to any Medicare-approved provider or facility that agrees to treat you and has not opted out of Medicare for services Original Medicare covers. [3] A PFFS plan may or may not have a network. If it has one, you can use the network providers who agreed to treat plan members, and you may also choose an out-of-network provider who accepts the plan's terms, though you might pay more. If it has no network, you can go to any Medicare-approved doctor or hospital that accepts the plan's payment terms and agrees to treat you. Not every provider will. [5] Some Special Needs Plans follow HMO network rules and some follow PPO rules, so ask which structure you are looking at. [3]

What to read before you enroll

Whatever the plan type, you will typically need prior authorization before the plan covers certain services or supplies. [3] A referral and a prior authorization are not the same step. A referral is the go-ahead to see a specialist, which HMO plans generally require and PPO plans do not. [1][2] Prior authorization is the plan's decision on a particular service or item. Read which services need it in the Evidence of Coverage. [7] This article does not explain appeals.

If you are in a Medicare plan, the plan sends an Evidence of Coverage each year, usually in the fall. Medicare's mailing guide lists September as the time to expect it, and it says the plan is the sender. [7] The document tells you what the plan covers, how much you pay, and more. [7] Review it for the coming year. If it does not arrive, contact the plan. [7]

The provider directory is the companion piece. You can find it on the plan's website, or you can ask the plan to send it. [5] Medicare suggests you ask how to tell whether your providers are in the network, what you pay in network, what you pay out of network, and what happens if a covered treatment is not available from an in-network provider. [5] Each year, during Medicare Open Enrollment, from October 15 through December 7, check whether your providers are in the plans you are considering. [5]

People with end-stage renal disease can join a Medicare Advantage plan. In many of those plans you can only use providers in the plan's network and service area, so confirm the dialysis center, the kidney doctor, or a transplant specialist before you join. [5]

When we sit down with a family in Greensboro or elsewhere in the Triad, we start with the home address and the names of the doctors they do not want to leave. An HMO can work well when those doctors are in the network and a primary care doctor coordinating referrals is acceptable. [1] A PPO can work well when you want the out-of-network option and you have asked what that visit will cost. [2] Neither line is a recommendation for every household. The directory and the Evidence of Coverage decide it. [5][7] If you are the adult child helping a parent, let your parent name the offices. A wide network is the wrong network when the clinic that knows the case is missing.

How we can help

Have more questions or want to get in touch? Visit https://thesih.com/contact/ or call (336) 937-7501.

Citations

1. Medicare.gov, "Health Maintenance Organizations (HMOs)" (2026)
2. Medicare.gov, "Preferred Provider Organizations (PPOs)" (2026)
3. Medicare.gov, "Compare types of Medicare Advantage Plans" (2026)
4. Medicare.gov, "Learn How Medigap Works" (2026)
5. Medicare.gov, "Understanding Your Medicare Advantage Plan's Provider Network" (2026)
6. Medicare.gov, "Joining a plan" (2026)
7. Medicare.gov, "Evidence of Coverage (EOC)" (2026)
8. Centers for Medicare & Medicaid Services, "Health Plans - General Information" (2024)