Most US plans want you to have one main doctor who knows you. The type of plan decides how free you are to see other doctors.
HMO (Health Maintenance Organization): you must use the plan's network, except in emergencies. You usually pick a primary care doctor, and you need a referral from that doctor to see a specialist. Lower cost, less choice.
PPO (Preferred Provider Organization): you can see in-network doctors and specialists without a referral. You can also go out of network, but you pay more. Higher premium, more choice.
EPO (Exclusive Provider Organization): network only, like an HMO, but often no referral needed.
POS (Point of Service): like an HMO with referrals, but some out-of-network care is covered at a higher cost.
HDHP (high-deductible health plan): a plan with a high deductible. It can come with an HSA (health savings account), where you save money before tax for medical costs.
What a primary care doctor does
A primary care provider (PCP) is your first stop for most health questions: check-ups, colds, blood pressure, long-term conditions, and sending you to a specialist. A PCP can be a family medicine doctor, an internal medicine doctor, a pediatrician for children, a nurse practitioner (NP) or a physician assistant (PA). NPs and PAs are trained clinicians who can examine you and prescribe medicines.
Find a primary care doctor
Log in to your insurance app or website and open Find a doctor.
Filter by in-network, primary care, your ZIP code, and languages spoken if you want a doctor who speaks your language.
Call the office and ask: "Are you accepting new patients?" and "Do you take my plan?" Give the plan name on your card.
Ask how long the wait is for a first visit. New-patient visits can take several weeks, so book early, before you are sick.
In an HMO, tell the plan which PCP you chose, in the app or by phone. Some plans assign one if you do not choose.
You see your PCP about a problem, for example knee pain.
The PCP sends a referral to an in-network specialist, for example an orthopedist.
Check that the referral was sent before your visit. Call the specialist's office to confirm.
Some care also needs prior authorization from the plan. The doctor's office usually handles it.
Seeing a specialist without a referral in an HMO. The plan may not pay.
Trusting an online list that is out of date. Always confirm by phone.
Waiting for an emergency to find a doctor.