Original Medicare is a federal health insurance program for eligible U.S. citizens and legal residents. It is funded in part by the FICA taxes you pay while working. It is individual health insurance that generally has a cost for each service. Here are the general rules for how it works: In most cases you can go to any doctor, health care provider, hospital, or facility that is enrolled in Medicare and accepting new Medicare patients. With a few exceptions, most prescriptions aren’t covered in Original Medicare. You can add drug coverage by joining a Medicare Drug Plan (Part D). In Original Medicare you don’t need to choose a primary care doctor or get a referral to see a specialist.

You generally pay a set amount for your health care (deductible) before Medicare pays its share. Then, Medicare pays its share, and you pay your share (coinsurance / copayment) for covered services and supplies. There’s no yearly limit for what you pay out-of-pocket. Part B has a premium and if your income is over a certain threshold, you may have to pay an additional amount called an IRMAA. You generally don’t need to file Medicare claims. The law requires providers and suppliers to file your claims for the covered services and supplies you get. Providers include doctors, hospitals, skilled nursing facilities, and home health agencies.