Coding with modifiers, part 1: Modifier 24 made easy

May 19, 2017 / By Camille Ruiz, RHIA

My colleagues and I were discussing the idea that modifiers have the most room for interpretation by professional fee coders, prompting a three-part blog series covering modifiers 24, 25 and 59. I hope the following will be a helpful tool when modifier 24 is required.

Purpose of Modifiers

Modifiers are two characters that identify a service or procedure has been altered but does not change the HCPCS or CPT code description when appended. Modifiers may or may not impact reimbursement. 

Modifier 24 unrelated Evaluation and Management Service by the Same Physician during the Postoperative Period

Modifier 24 is appended to an E/M code only, not a surgical code, to distinguish an unrelated visit that is not aftercare to a procedure during the global period.   


Documentation must support modifier assignments. Modifiers should not be used solely to bypass National Correct Coding Initiative (NCCI) edits. Modifier 24 does affect how the claim is processed and reimbursed. A general rule of thumb for CMS global period is a postoperative period of 10 days for minor procedures and 90 days for major procedures. Keep in mind that CMS and commercial payers have different global periods. It is important for the coder to be familiar with the differences. 


Use of Modifier 24:

  • Assign only to E/M levels for physician claims, not the surgical code.
  • Assign to E/M levels performed by the same physician in the postoperative period unrelated to the original procedure.
  • A diagnosis code unrelated to the surgical procedure must assigned related to the E/M level.
  • Assign if managing chemotherapy or immunosuppressive therapy during the postoperative period.

Do not use Modifier 24:

  • Do not assign if the E/M level is performed on the same day of surgery by the same physician (See Modifier 25).
  • Do not assign after the postoperative period.
  • Do not assign if the physician is part of the same practice as the physician who performed the procedure or covering surgeon.
  • Do not assign if the complication is considered part of the surgical procedure such as postoperative ileus after GI surgery.
  • Do not assign for postoperative routine care or incidental services provided.  
  • Do not assign if the patient requires a subsequent procedure due to surgical complications or postoperative condition present due to the initial procedure. (See modifier 78).
  • Do not assign if the reason for the visit is related to the surgical procedure such as wound dehiscence or infection.

Note: Although a dehiscence or infection is a new problem with a different diagnosis as the surgical diagnosis, CMS considers wound infection as related to the procedure during the global period. 

I hope these tips clear up or confirm your current assignment methods. Keep coding!

Camille Ruiz is an outpatient CDI consultant at 3M Health Information Systems.