Laboratory Question for the Week of April 6, 2026

Question:

When is it appropriate to use modifier 59 for repeat procedures, and what documentation is required to support its use?

Answer:

In the instance of billing for a repeat of the same procedure, first check the Medically Unlikely Edit (MUE) limitation to determine if the unit of service is allowed to be billed in quantity without a modifier. If it is determined that use of a modifier is appropriate to resolve a claim edit, confirm appropriate use of modifier 59 by reviewing the payer guidelines applicable to your facility. Note that the AMA definition of modifier 59 puts emphasis on the terms “different” and “separate,” as seen in the following excerpt from the CPT manual. Modifier 59 is used to identify procedures or services, other than E/M services, that are not normally reported together but are appropriate under the circumstances. Documentation must support a different session, different procedure or surgery, different site or organ system, separate incision or excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual.

This question was answered in our Coding Essentials for Laboratories. For more hot topics relating to laboratory services, please visit our store or call us at 1.800.252.1578, ext. 2.