Have Your Patients Got New MBI (Medicare Beneficiary Identifier)?

The Centers for Medicare & Medicaid Services (CMS) is mailing the new Medicare cards with the (MBI) Medicare Beneficiary Identifier in phases by geographic location. There are 3 ways you and your office staff can get MBIs:

Ask your Medicare patients:

Ask your Medicare patients for their new Medicare card when they come for care. If they haven’t received a new card at the completion of their geographic mailing wave, give them the “Still Waiting for Your New Card?” handout or refer them to 1-800-Medicare (1-800-633-4227).

Use the MAC’s secure MBI lookup tool:

You can look up MBIs for your Medicare patients when they don’t or can’t give them. Sign up for the Portal to use the tool. You can use this tool even after the end of the transition period – it doesn’t end on December 31, 2019.

Check the remittance advice:

Starting in October 2018 through the end of the transition period, CMS will also return the MBI on every remittance advice when you submit claims with valid and active Health Insurance Claim Numbers (HICNs).

You can start using the MBIs even if the other health care providers and hospitals that also treat your patients haven’t. When the transition period ends on December 31, 2019, you must use the MBI for most transactions.

Ask your patient for their card. If they have not received a new card, ask them to look for a plain white envelope from the Department of Health and Human Services or sign in to MyMedicare.gov to get their new number or print an official card; or call 1-800-Medicare (1-800-633-4227). Use your Medicare Administrative Contractor’s lookup tool. Sign up for the Portal to use the tool.

Why new MBI (Medicare Beneficiary Identifier)?

The Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) requires CMS to remove Social Security Numbers from all Medicare cards by April 2019. A new randomly generated Medicare Beneficiary Identifier, or MBI, is replacing the SSN-based HICN.

Using new MBI (Medicare Beneficiary Identifier)


The new MBI is noticeably different than the HICN. Just like with the HICN, the MBI hyphens on the card are for illustration purposes: don’t include the hyphens or spaces on transactions. The MBI uses numbers 0-9 and all uppercase letters except for S, L, O, I, B, and Z. CMS exclude these letters to avoid confusion when differentiating some letters and numbers (e.g., between “0” and “O”).


Use the MBI the same way you use the HICN today. Put the MBI in the same field where you’ve always put the HICN. This also applies to reporting informational only and no-pay claims. Don’t use hyphens or spaces with the MBI to avoid rejection of your claim. The MBI will replace the HICN on Medicare transactions including Billing, Eligibility Status, and Claim Status.

The effective date of the MBI, like the old HICN, is the date each beneficiary was or is eligible for Medicare. Until December 31, 2019, you can use either the HICN or the MBI in the same field where you’ve always put the HICN. After that, the remittance advice will tell you if CMS rejected claims because the MBI wasn’t used. It will include Claim Adjustment Reason Code (CARC) 16, “Claim/service lacks information or has submission/billing error(s).” along with Remittance Advice Remark Code (RARC) N382 “Missing/incomplete/invalid patient identifier”.

The MBI does not change Medicare benefits. Medicare beneficiaries may start using their new Medicare cards and MBIs as soon as they get them. Use MBIs as soon as your patients share them. The new cards are effective the date beneficiaries are eligible for Medicare. Medicare Advantage and Prescription Drug plans continue to assign and use their own identifiers on their health insurance cards. For patients in these plans, continue to ask for and use the plans’ health insurance cards.

Source: New Medicare Beneficiary Identifier (MBI) Get It, Use It

                Still Waiting for Your New Card?