When you enroll in Medicare you’ll be issued a Medicare card. On that card, there’s a very important number called your Medicare claim number. Today, we’re going to talk about why that number is so important for your Medicare coverage, then dive into the three ways your Medicare number will be used. Let’s get started. 

What is a Medicare Card?

Medicare Cards look much like other insurance cards. They contain information like your name and your Medicare effective dates. They also have an 11-digit number printed on them. This 11-digit number is called your Medicare number or claim number. 

For years, the claim number printed on Medicare cards was actually the beneficiary’s social security number. Thanks to identity theft concerns, Medicare now issues each person a unique and random 11-digit sequence of letters and numbers as their claim number. 

Three Ways Your Medicare Number Will Be Used

Your Medicare claim number is used in three specific (and very important) ways.

Proof of Eligibility 

First, your claim number provides proof of your Medicare eligibility. Just like your Social Security number provides proof that you've been paying into Social Security and will one day be eligible for benefits, your Medicare claim number proves that you or your spouse has paid into the Medicare system for at least 40 quarters and are eligible for Medicare insurance. 

Enrollment Into Additional Insurance

Second, your Medicare claim number allows you to enroll in other insurance plans. Why would you want to get additional insurance if you’re on Medicare? Although original Medicare A and B provide good coverage, they do not cover everything. There are six gaps in original Medicare and if you fail to get additional coverage, you’ll have to pay for these gaps out of your own pocket. Most people don’t want the financial risk, so they enroll in other insurance plans. 

To enroll in additional coverage (like a Prescription Drug Plan or Advantage Plan), you’ll be required to provide your Medicare claim number to prove you’re eligible to enroll in additional Medicare coverage. 

Processing Claims

Third, your Medicare claim number ensures both Medicare and your additional insurance coverage pays your medical claims. For example, if you decide to get additional coverage in the form of a Supplemental plan, your claim number is the only way to ensure your bills are covered. 

Here’s how it works: When you’re enrolled in a Supplemental Plan, Medicare pays your medical bills first, then sends the remaining balance to your Supplemental policy. So let’s say you go to the hospital for surgery. After the surgery, your doctor sends the bill (along with your claim number) directly to Medicare. Thanks to your claim number, Medicare knows to pay the bill first, then sends it on to your Supplemental insurance company. Without the Medicare claims number, Medicare wouldn’t be able to pay their part for your surgery or send the remaining balance to your Supplemental plan provider. 


The Medicare claim number proves your eligibility to enroll in Medicare, allows you to enroll in additional coverage, and is used by Medicare and other insurance providers during the claims process. 

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