It used to be pretty simple—either your doctor accepted your insurance or didn’t. But all that has changed. These days, your doctor may accept your insurance (from Medicare or a private insurer) only under certain circumstances. And if you think your doctor’s services are included but they’re not, you could be blindsided by a whopping out-of-pocket cost to you. Fortunately, you can avoid getting hit with a big bill—even if your doctor participates in this medical version of musical chairs.

Here’s where the trouble starts: In today’s world of medicine, many doctors are joining more than one group practice. A surgeon, for example, may have to join two or more group practices in order to gain treatment privileges at particular hospitals (many hospitals have exclusive agreements with certain groups). And while one practice might accept your insurance, the other practice might not. In addition, some groups with multiple locations might accept your insurance only if you see the doctor at one of their particular offices! Adding to the confusion, some group practices also allow doctors within the practice to “opt out” of certain insurance plans, while other doctors in the practice accept it.

The problem—especially if you are in a plan that requires you to use “network” doctors—is that if you checked for your doctor’s name on your insurance company’s “network of participating doctors” roster, it may show up there. But unless you see him/her in the right practice and/or right location, your doctor might not be considered “in network”—in which case your claim will be treated as an “out-of-network” visit or possibly denied. How to avoid this frustrating gameand a surprise bill… 

• Talk to the right people. Obviously, the first thing to do is ask the person who books your appointment whether the doctor accepts your insurance. But don’t stop there. Confirm with the person who is in charge of billing that your insurance will be accepted in that location and by the doctor you’re seeing. This double-tiered verification is necessary, since the person who books appointments may not always know for sure if your particular insurance plan is one the practice can accept. Special alert: If you are enrolled in a Medicare Advantage HMO or Medicare PPO and a doctor or his practice tells you that his service is covered by your plan, and the claim is later denied because the doctor or practice turns out not to be “participating,” the law forbids the doctor or practice from billing you for the service. If you receive a bill, do not pay it and immediately call Medicare’s 800-MEDICARE hotline for assistance. 

• Check with your insurer, too. Just to make sure that the verification you got from your doctor’s office is correct, call your insurance company and specifically ask if the doctor you’re planning to see, at the location where the service is going to be rendered (especially important if you live near a state line and your doctor has offices in two or more states) is considered a “participating practitioner.” While you’re at it, also ask whether the service you will be receiving from the doctor is covered by your plan. Warning: Do not rely on the insurer’s online list of participating doctors, since these lists are notoriously out of date. If you’re on Medicare, go to Medicare.gov and click on “Find doctors & other health professionals” to confirm that your doctor is covered. To confirm that a specific service is covered, call 800-MEDICARE.