New Medicare cards without Social Security numbers will be sent out starting in April 2018, according to CMS, meeting a deadline set by Congress to replace all the cards by April 2019.

Instead of the Social Security-based Health Insurance Claim Number (HICN), the new cards will use a unique, randomly assigned combination of letters and digits to be known as the Medicare Beneficiary Identifier (MBI).

“We’re taking this step to protect our seniors from fraudulent use of Social Security numbers which can lead to identity theft and illegal use of Medicare benefits,” said CMS Administrator Seema Verma, MPH. “We want to be sure that Medicare beneficiaries and healthcare providers know about these changes well in advance and have the information they need to make a seamless transition.”

There's no prototype available showing what the new card will look like. CMS has said the new MBI will be a 11-character code to more easily distinguish it from 9-digit Social Security numbers. 

Removing Social Security numbers on Medicare cards has been discussed for years. A 2012 Government Accountability Office (GAO) report said all the available options to CMS would cost at least $800 million, including the option it later decided to take—replacing the number with a brand new identifier. In the meantime, CMS said Medicare beneficiaries have become common targets for identity theft, with reported incidents among people aged 65 or older increasing from 2.1 million to 2.6 million between 2012 and 2014.

For providers, CMS has promised an easy transition. During a 21-month period after the cards begin to be rolled out, providers will be allowed to use either the MBI or the old HICN. The agency also said both providers and beneficiaries will be able to “use secure look up tools that will support quick access to MBIs when they need them.”