Pathology/Lab Coding Alert

Question: How should we code a claim when the units performed exceed the Medicare MUE?

Arkansas Subscriber

Answer: You can override medically unlikely edit (MUE) limits by using specific modifiers when you can document medical necessity for the service.

For instance: If the pathologist evaluates two flow cytometry panels for two distinct medical conditions for the same patient on the same day, one with 2 markers and one with 8 markers, you should report two units of 88187 (Flow cytometry, interpretation; 2 to 8 markers) for the pathologist's interpretation. Because CMS assigns an MUE of "1" to 88187, you'll need to use a modifier to override the MUE.

Do this: Report 88187 on one claim line and 88187-59 (Distinct procedural service) on a separate claim line.

Other modifier options: Medicare's MUE frequently asked questions # 8736 states that "Since each line of a claim is adjudicated separately against the MUE of the code on that line, the appropriate use of [CPT] modifiers to report the same code on separate lines of a claim will enable a provider/supplier to report medically reasonable and necessary units of service in excess of an MUE."

Specifically, CMS states that you can use one of the following modifiers to override MUEs:

• 76 -- Repeat procedure or service by same physician or other qualified health care professional
• 77 -- Repeat procedure or service by another physician or other qualified health care professional Anatomic modifiers such as RT (Right side), LT (Left side)
• 91 -- Repeat clinical diagnostic laboratory test
• 59 -- Distinct procedural service.

Although Medicare added modifier GD (Units of service exceed medically unlikely [MUE] value and represent reasonable and necessary services) in 2008, CMS has not issued instructions for its use. At this time, you should continue to follow the FAQ #8736 instruction for modifier use instead of implementing modifier GD.