MedicaidAdministrativeMedium impact
Reminder Regarding Receipt of Second 999 Implementation Acknowledgement
Illinois Medicaid - HFS·IL·Education
Effective date
Apr 23, 2026
We identified it
Jun 16, 2026
Summary
Illinois Medicaid is reminding providers about the 999 Implementation Acknowledgement process for electronic claim submissions. Providers must monitor for and respond to second 999 acknowledgements that indicate claim rejections, correcting errors and resubmitting within timely filing deadlines.
Action Required
Immediately: Billing team must monitor all EDI 837 claim submissions for second 999 Implementation Acknowledgements from Illinois Medicaid. When received, identify rejected ST/SE levels, correct errors, and resubmit claims before timely filing deadlines. If claims don't appear in MEDI system within 30 days of submission, resubmit the claims. Failure to resubmit corrected claims timely will result in claim denials with no payment liability from the state.