Question: If our clinic can show medical necessity for multiple units of a single procedure that we believe exceeds an MUE, do we have any way to "override" the edit as we do for CCI edits? Florida Subscriber Answer: As of Jan. 1, 2008, Medicare provides a HCPCS Level II modifier for a scenario such as you describe -- GD, Units of service exceed medically unlikely edit (MUE) value and represent reasonable and necessary services. Questions remain: No Medicare direction about using this modifier was available at press time. In fact, Medicare's current "Frequently Asked Questions" about medically unlikely edits still suggests listing multiple procedures on separate lines and using an appropriate modifier such as 91 (Repeat clinical diagnostic lab test) or 59 (Distinct procedural service). Caution: The National Correct Coding Initiative Policy Manual states that occurrences when you need to override an MUE should be "uncommon," and you may be coding incorrectly if you override the edits frequently. You may want to contact your carrier for further direction before you begin using modifier GD, and be prepared to submit additional paperwork to support the use of this modifier.