CMS Technical Instructions: MSIS-IDENTIFICATION-NUM in T-MSIS submissions

This reporting reminder outlines the reporting expectations of assigning unique MSIS IDs in T-MSIS.

MSIS-IDENTIFICATION-NUM which is found in the ELG, CIP, CLT, COT, CRX, and TPL Files.

MSIS ID is a required field and should be unique for each individual. When reporting in T-MSIS, each individual should be assigned one unique MSIS ID. When an individual dis-enrolls and then re-enrolls in Medicaid, the unique MSIS ID remains the same to ensure the individual’s enrollment and services can be attributed to a specific individual over time despite the interruption in enrollment.

Deemed newborns are an exception to this reporting reminder, as it is allowable for them to share an MSIS ID within certain circumstances. Please see the existing guidance, Reporting Shared MSIS Identification Numbers, in the T-MSIS Data Guide for more information on reporting deemed newborns in T-MSIS.