The U.S. Centers for Medicare & Medicaid Services (CMS) has decided to leave the onus on Medicare administrative contractors (MACs) to make coverage determinations regarding the Allomap test for heart transplant rejection despite a request for a non-coverage policy. As was the case in the decision to allow MACs to determine coverage for total artificial hearts, the CMS said that the low annual rate of utilization of the Allomap, by Caredx Inc., of Brisbane, Calif., suggested that the MACs are in a better position to make the appropriate call regarding coverage.