DME MACs A and B notified providers last week that the Positive Airway Pressure and Respiratory Assist Devices local coverage determinations have been revised, effective for dates of service on or after Sept. 1, 2009. The revised information is in the Documentation Section and outlines the use of additional modifiers to indicate that an item is not medically necessary and whether or not a waiver of liability statement (i.e., Advance Beneficiary Notice) is on file. Read the Positive Airway Pressure local coverage determination and Respiratory Assist Devices local coverage determination revisions.