Our compliance department requires that MDM be 2 of the 3 componets for an established patient, where as it is 3 of 3 for a new patient. This is to unsure that MDM is being met. But you can always refer to your Medicare provider for their requirements. As a rule of thumb that I use when I am abstacting a chart I refer to the MDM to get an idea of where the code might fall. Hope this helps!