Medicare - Coordination of Benefits Customer FAQ

Typically, Medicare Part B does cover MRI scans when they are deemed to be medically necessary by your doctor. However, your provider may need to get prior authorization from Medicare before you undergo the procedure. This is to ensure that Medicare agrees to cover the scan. It's always best to check with your doctor and Medicare directly to know if prior approval is required for your specific case.

Medicare usually covers medically necessary services that meet their criteria. If your blood test for prothrombin time was not covered, it could be due to several reasons. Your doctor might not have indicated that the test was medically necessary, or there might have been coordination of benefits issue if you have other insurances. In the latter case, Medicare may not be the primary payer. It's also possible that you've exhausted your benefit limit. Double check these factors to ascertain why the service was not covered.