What’s the difference between Modifiers 58 and 78?

What’s the difference between Modifiers 58 and 78?

One of the most challenging aspects of medical coding are modifiers— Medical coders find themselves wondering:

  • What do modifiers mean and when do I use them? 
  • Which codes need modifiers?” 
  • What modifiers do I need to append, and to what codes? 
  • Do I even need a modifier? 
  • What if I add a modifier and don’t need one?
  • What if I don’t add a modifier and need one?
  • Will I have a bunch of angry doctors coming after me?

The stress and struggle of modifiers are real. In fact, two of the most misused modifiers are Modifier 58 and Modifier 78 because, at first glance, they look the same—they even share similar verbiage—and after a long day of coding, it is too easy to skim through the modifier language and append the wrong code. On the other hand, some coders use these modifiers interchangeably because of a misunderstanding of the codes’ definitions. These codes, though, code for separate circumstances and, thus, cannot be used interchangeably. 

However, Modifiers 58 and 78 contain a seemingly subtle but significant difference that separates them. Before discussing this difference, it is important to understand the purpose of modifiers and the definitions of Modifiers 58 and 78 first.

Modifiers and their Purpose

A medical coding modifier consists of two characters added to a CPT or HCPCS Level II code. The characters are either letters or numbers preceded by a hyphen like this: 19318-50. The purpose of appending modifiers to procedure codes is to provide additional, necessary information about the procedure, service or supply without changing the meaning of the code. It is the second part of the story of the encounter. The code with an appended modifier in the example above tells us the following:

  • 19318= Breast reduction 
  • 50= Bilateral procedure

The doctor performed a breast reduction surgery (19318) on both breasts (50), not just one. Without modifier 50, the doctor would not receive proper compensation for all work performed. The above example seems straightforward and easy to comprehend. However, other modifiers seem to be so similar that it proves challenging for the medical coder to choose the correct one, as is the case with Modifiers 58 and 78.

Modifier 58

The CPT Manual defines Modifier 58 as a “staged or related procedure or service by the same physician or other qualified healthcare professional during the postoperative period” (2023). When a procedure has Modifier 58 appended to it:

  • The procedure was planned
  • The procedure took place during post op
  • The procedure was completed by the physician or qualified healthcare professional who performed the initial procedure

An example of a procedure code needing Modifier 58 is when the initial surgeon completes a biopsy on a patient and sees malignant cells in the sample, and schedules and performs a procedure to remove the cancerous cells. Since this second procedure is performed by the same surgeon and planned, Modifier 58 is appropriate.

In short, the initial procedure and the procedure performed during the postoperative period were both planned and completed by the same physician or qualified healthcare provider. Both patient and physician knew the post op procedure would occur during the encounter. 

Modifier 78

Though Modifier 78 shares similarities with Modifier 58, there are significant differences between the two codes. The CPT Manual provides the following definition of Modifier 78: “Unplanned return to the Operating/Procedure Room by The Same Physician or Other Qualified Health Care Professional Following Initial Procedure for a Related Procedure During the Postoperative Period” (CPT, 2023). 

From this definition, coders know the following about the procedure to which it is appended:

  • Related procedure to the initial procedure
  • Performed by the same physician or qualified health care professional
  • Performed during Post Op
  • Unplanned

Modifier 78 describes a situation in which a patient goes to a facility for a planned procedure or service but, during post op, must return unexpectedly to the operating room for a related procedure. This need for another procedure could be due to complications resulting from the initial procedure. Neither patient nor the doctor scheduled the second procedure in advance. 

An example of a situation in which a coder would append Modifier 78 would be when a doctor performs a cesarean on a patient, but while in post op, the patient experiences bleeding and must return to the OR for an additional procedure by the same physician (What are medical…?). Since this procedure was not planned, Modifier 78 is appropriate. 

Difference Between Modifiers 59 and 78

Modifiers 58 and 78 share many similarities. They both include:

  • Related procedures performed in postop
  • Procedures performed by the same physician or qualified healthcare professional

The above similarities make the two modifiers seem interchangeable, but they are not and cause confusion for many coders because of the one difference between them:

Modifier 58 codes for a planned procedure, while Modifier 78 codes for an unplanned procedure. Though the procedures appended with both modifiers are performed by the same doctor or health care professional as the planned initial procedure, the procedure performed after the initial procedure during the postoperative period may or may not be planned. 

Modifier 58= planned post op procedure or service

Modifier 78= unplanned post op procedure or service. 

The difference between the two lies within the coding language. Here is the coding language for both modifiers below:

Modifier 58: 

Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period (CPT, 2023)

Modifier 78: 

Unplanned return to the Operating/Procedure Room by The Same Physician or Other Qualified Health Care Professional Following Initial Procedure for a Related Procedure During the Postoperative Period (CPT, 2023)

When reading the coding language forensically and carefully, it is clear these two modifiers share so many similarities except for one notable difference. Modifier 58 reads “staged,” while Modifier 78 reads “Unplanned,” hence, the necessity of reading (and coding) forensically. 

The best way to know which code should be used is to determine whether the second procedure or service was planned or unplanned. If planned, choose Modifier 58. If unplanned, select Modifier 78. 


While learning which modifiers to append to medical codes can be tricky, understanding the subtle yet not so subtle differences between Modifiers 58 and 78 can help all coders, especially novices, feel more confident they are appending the correct code. Reading and coding forensically help coders improve their skills and gain a better eye for details, which in turn, results in gaining more confidence as a medical coder. This confidence and additional coding practice will help coders gain knowledge and expertise that will enable them to master coding.


How to choose: Modifier 58, 59, 78, 79. MedProdDispolsal.

MCG 2023 Absolute Medical Coding Institute

About the Blogger:

Victoria Smith is an AMCI student and intern preparing for the CPC exam. She is also a writer, editor, teacher, and lifelong learner.