Medicare is a complex federal insurance program available to people over the age of 65 years and people with certain disabilities. When you become eligible and receive your Medicare card, you will notice a number with a letter or letters at the end. Though it may be confusing, generally the letter suffix has no effect on your health care coverage.
Your Medicare Card
Your red, white and blue Medicare card will include your name and gender; whether you are enrolled in Parts A and B, which refer to hospital and medical coverage; and the effective dates of your coverage. Your card will also include your Medicare number.
Your Medicare Number
Your Medicare number may also be called your Medicare claim number or your health insurance claim number. It is comprised of your Social Security number, or the Social Security number of the person through whom you became eligible for Medicare, and a letter or letters at the end. The letter suffix refers to the manner in which you became eligible for Medicare.
There are more than 30 letter codes that may be attached to a Social Security number to make a Medicare number with A being the most common. An A at the end of your Medicare number indicates that you receive Medicare because you paid into the program while you were working. In this case, your Medicare number is your Social Security number followed by the letter A.
If your Medicare eligibility is based on someone else's work history, you will have a completely different number. For example, if you receive Medicare because you are the wife of the wage earner, and you are 62 years of age or older, your Medicare number will be your husband's Social Security number followed by the letter B.
Other commonly used codes refer to an aged husband of a wage earner, a widow or widower of a wage earner, or a disabled wage earner (see References).
When you receive medical services, your medical provider will send a bill for services to Medicare. They must include your Medicare number in order to be paid for their services. If you send your own claim to Medicare, you must also include your Medicare number in order to be reimbursed.
On occasion, your Medicare number may change. For example, the widow of a wage earner who remarries and receives Medicare through her new husband will receive a new Medicare number made up of her new husband's Social Security number plus the letter or letters that indicate her status as his wife. In such cases, the Social Security Administration will change your Medicare number and send you a new card.