All inquiries and comments regarding Trading Partner registration, connection set-up, transaction testing, and the submission of 270/271 transactions and interpretation of their data should be directed to the MCARE Help Desk (MCARE).
MCARE is typically open Monday through Friday, from 7 am to 7 pm ET. MCARE is closed on federal holidays and may have modified hours on the day before or after a holiday. MCARE will send an email reminder to subscribed users two business days before a federal holiday.
If you encounter a significant HETS issue outside of operational hours, call the MCARE Help Desk and leave a voicemail.
- mcare@cms.hhs.gov
- 1-866-324-7315
Note: The MCARE email address is monitored during normal business hours. Emails are typically answered within one business day.
MCARE cannot assist in the resolution of benefit-related discrepancies. Questions regarding eligibility/benefit data for Medicare Part A and Part B should be directed to the appropriate regional MAC. Eligibility/benefit questions about MA, Part D, and MSP should be directed to the appropriate plan(s) identified in the 271 response.
Listed below are holiday closure dates and times.
Date | Holiday | MCARE Operational Status |
|---|---|---|
| Thursday, December 25, 2025 | Christmas Day | Closed |
| Friday, December 26, 2025 | Day after Christmas Day | Open 8:00 AM - 5:00 PM ET |
| Wednesday, December 31, 2025 | New Year's Eve | Open 8:00 AM - 5:00 PM ET |
| Thursday, January 1, 2026 | New Year’s Day | Closed |
| Monday, January 19, 2026 | Birthday of Martin Luther King, Jr. | Closed |
| Monday, February 16, 2026 | Washington’s Birthday | Closed |
| Monday, May 25, 2026 | Memorial Day | Closed |
| Friday, June 19, 2026 | Juneteenth National Independence Day | Closed |
| Friday, July 3, 2026 | Independence Day | Closed |
| Monday, September 7, 2026 | Labor Day | Closed |
| Monday, October 12, 2026 | Columbus Day | Closed |
| Wednesday, November 11, 2026 | Veterans Day | Closed |
| Thursday, November 26, 2026 | Thanksgiving Day | Closed |
| Friday, November 27, 2026 | Day after Thanksgiving Day | Open 8:00 AM - 5:00 PM ET |
| Friday, December 25, 2026 | Christmas Day | Closed |
| Thursday, December 31, 2026 | New Year's Eve | Open 8:00 AM - 5:00 PM ET |