As a reminder, Tufts Health One Care became a Dual Eligible Special Needs Plan (D-SNP) as of Jan. 1, 2026. As part of this product update, all Tufts Health One Care members were assigned new member ID numbers and issued new ID cards. 

To ensure uninterrupted care for members — and that your claims are processed and paid in a timely manner next year — please update your billing systems to reflect new ID numbers for One Care members, if you have not already done so.

Claims submitted for services delivered in 2026 using a prior ID number will be denied due to member ineligibility. You will need to resubmit those claims with the correct 2026 member ID number.

One Care member ID numbers are formatted similarly to IDs for Tufts Health Plan senior products and do not include an “01” suffix. 

 Here’s a sample image of the new Tufts Health One Care member ID:

 

You can also look up the updated member ID number in the secure provider portal.

Additionally, as part of the transition, any active prior authorizations with an end date after Dec. 31, 2025 were automatically transferred to the member’s new ID number. These authorizations will remain valid, and no further action is required on your part. To avoid delays and unnecessary administrative work, please do not submit a duplicate authorization request if a valid authorization already exists. 

You may review authorization status via the Tufts Health Plan secure portal (refer to the MHK Portal User Guide for step-by-step instructions).