Final answer:
The fourth level of the Medicare appeals process involves a review by the Medicare Appeals Council, and the request for this review must be filed within 60 calendar days following the receipt of the ALJ's decision.
Step-by-step explanation:
Fourth Level of Medicare Appeals Process
The fourth level of the Medicare appeals process is the review by the Medicare Appeals Council. Upon receipt of an Administrative Law Judge's (ALJ) decision, if a party is dissatisfied, they have the option to request a review by the Appeals Council. This request must be filed within 60 calendar days from the receipt of the ALJ's decision. The Appeals Council will then review the decision, and it has the power to affirm, modify, or reverse the ALJ's decision or remand the case back to the ALJ for further review.