Notification of the rejection of a request for external review for failure to meet requirements in 958 CMR 11.15 shall be issued by the Office of Patient Protection to the Patient or the Patient’s Authorized Representative within 72 hours of a receipt of a request for an expedited review and within six business days of a receipt of a request for all other reviews. The notification shall set forth the specific reason why the request has been determined ineligible for an external review.