Final answer:
Mrs. Duarte should appeal the Medicare determination by filing an appeal within 120 days of receiving her MSN, and if necessary, ask for an independent review after the MAC's decision.
Step-by-step explanation:
Mrs. Duarte should request a reconsideration of the decision by a qualified independent party within 60 days of the date she received the MSN in the mail. If Mrs. Duarte disagrees with a determination on her Medicare claim as indicated on her Medicare Summary Notice (MSN), she has the right to appeal. The correct course of action would be to file an appeal of this initial determination within 120 days of the date she received the MSN in the mail. According to Medicare guidelines, an appeal must be filed within this timeframe to request a reconsideration by her Medicare Administrative Contractor (MAC). If after the MAC's decision she still disagrees, she can then request an independent reconsideration.