My nephew doesn’t have health insurance from an employer, so he recently purchased a policy through the Health Insurance Marketplace, the federal program established under the Affordable Care Act (ACA). He went online to search for policies available in his state and made lots of phone calls before making his choice. A few days later, I asked him what the plan covered. There was silence. He really didn’t know very much about what was covered by the plan he chose. 

My nephew is not unusual. Most of us, including the majority of people on Medicare, really do not have a good understanding of what is and isn’t covered by their health insurance policies. And many of us have been shocked to get a bill that can run in the hundreds or even thousands of dollars for the total cost of a service we thought was covered. My advice… 

• Watch out for “exclusions.” It may sound obvious, but you need to read your policy. By law, it must spell out what types of services (not necessarily the exact service or procedure) are covered in your plan. It may say “hospital inpatient services” or “ambulance services” are covered and then describe what percentage of the cost the plan will pay. But don’t stop there. All policies must divulge what is not covered (often called “exclusions”). Each year, for example, you may get only so many allowable trips in an ambulance…or a specified number of visits to certain practitioners, such as a chiropractor or mental-health specialist. If you’re confused about any of the language in the policy or want to find out if a specific procedure or service is covered, call the insurer (see below). Insider tip: The ACA requires Marketplace and other federally approved plans, including Medicare and Medicaid, to provide federally mandated preventive services, such as flu shots, mammograms and diabetes screening, at no additional cost above your premium (no co-pay or deductible). For the complete list, go to HealthCare.gov and search “What Marketplace Health Insurance Plans Cover.” If your employer provides your health coverage, check directly with the insurer.

• Tap into new technologies. Medicare has introduced the app What’s Covered that you can download for free onto your smartphone or tablet. To get this app, go to the Apple App Store or Google Play. It allows you to look up a service/procedure (such as an MRI, diabetes screening, lab test, etc.) to see if it is covered by traditional Medicare…what percentage you pay…plus a list of free preventive services you may get. Even if you are in a Medicare Advantage plan, in which co-pays and deductibles are different from traditional Medicare, it is helpful, since all Advantage plans must provide, at a minimum, the same services as traditional Medicare. Insider tip: Many health plans now provide similar access through apps or directly on their websites. Check with your insurer.

 • Pick up the phone. To find out if your policy covers a specific procedure or service, you can also simply call your insurance company’s customer-service number. If you are on Medicare, call 800-MEDICARE (633-4227) and ask if the service you need is covered and how much you will have to pay. Helpful: It’s often quicker to get through if you call later in the week and later in the day.