Pathology/Lab Coding Alert

Question: Sometimes our pathologist exceeds the MUE for tests such as FNA exam. Are we allowed to bill all units performed, and what can we do to avoid denials?

Arkansas Subscriber

Answer: If your pathologist exceeds the number of units of service allowed under Medicare’s Medically Unlikely Edits (MUEs), you can bill for the full service you performed, under certain circumstances.

First: the medical record should demonstrate medical necessity for each of the tests performed. Diagnosis codes, physician orders, and descriptions of distinct tests or specimens could satisfy the requirement. For instance, if the pathologist diagnoses and reports on fine needle aspirate (FNA) specimens from four different sites, you can report four units of 88173 (Cytopathology, evaluation of fine needle aspirate; interpretation and report) even though 88173 has an MUE limit of three.

Second: Use an appropriate modifier to override an MUE limit when documentation demonstrates medical necessity for the number of units performed. You should report the same code on separate claim lines with the appropriate modifier, since CMS evaluates each claim line against the MUE value.

According to CMS, CPT^® modifiers such as 76 (Repeat procedure by same physician), 77 (Repeat procedure by another physician),91 (Repeat clinical diagnostic laboratory test), and 59 (Distinct procedural service), and anatomic modifiers (e.g., RT, LT, F1, F2) will enable a provider/supplier to report medically reasonable and necessary units of service in excess of an MUE value. Use modifier 59 only if no other modifier describes the service.

CMS doesn’t publish all MUEs, but you can find the public MUE table at www.cms.gov/Medicare/Coding/NationalCorrectCodInitEd/MUE.html.