How To Approach Ambiguous CPT Modifiers?

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modifier 79

In a perfect world, CPT modifiers are used without any issues to add additional information regarding a service provided by a physician. Sadly, we don’t live in a perfect world, and certain modifiers like modifier 79, for example, can cause significant billing problems. 

The thing is, the definition of some modifiers is very ambiguous so the confusion around them is justified. That is to say, if you’re a medical biller and you’re puzzled by these modifier codes, it might not be just you.

Making a mistake can have serious consequences and result in denied claims. Thus, knowing whether to use modifier 79 over modifier 59 is vital if you don’t want to end up in a world of trouble. 

We’ll do our best by clarifying the definitions of different codes and explaining when you should use each one. 

What are the most problematic modifiers?

The ambiguity in the definitions we mentioned refers to CPT modifiers. 58, 78, 79, 59, and 24 that are applied to surgery claims. These definitions are taken from the official site of the Center for Medicare and Medicaid Services (CMS):

1. Modifier 24: Unrelated evaluation and management (E/M) service by the same physician during a post-operative period
2. Modifier 58: Staged or related procedure or service by the same physician during the post-operative period
3. Modifier 59: Distinct Procedural Service: Under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-E/M services performed on the same day
4. Modifier 78: Unplanned return to the operating or procedure room by the same physician following the initial procedure for a related procedure during the post-operative period
5. Modifier 79: Unrelated procedure or service by the same physician during a post-operative period.

Breaking those definitions down, it’s easy to see where the confusion comes from. For example, the wording of modifiers 78 and 58 is unclear. If we were to go by what’s presented in the CMS definitions, both modifiers apply to the post-op period and could easily refer to the same procedure. 

The reason why this trips up medical professionals is that even though modifier 58 applies to staged procedures and 78 refers to unplanned procedures, the former also uses the phrase or related. This could indicate that both modifiers could be used interchangeably for a related, unplanned procedure. 

Others, like modifier 79 aren’t exempt from confusion either, which is why we will break down each of them in detail.

Modifier 58 explained

As described by CMS, this modifier indicates the procedure was:

1. Planned, either at the time of the first procedure or prospectively.
2. More extensive than the first procedure.
3. For therapy after a diagnostic surgical procedure.

However, the CMS doesn’t clarify if the conditions described above are separated by the words and or. This is why medical professionals generally assume that the conditions described should be separated by or. In other words, any of the conditions can justify the use of this modifier.

To clarify it further, modifier 58 is always about a patient returning to the OR as it refers to the related procedure in the post-op period. Additionally, the key factor in determining whether a procedure is covered by modifier 58 is if the doctor knew about the medical procedure before the first, related operation was completed. 

A good example of such a scenario would be if a surgeon performed a biopsy. Let’s say that the sample was found to be cancerous, and afterward, the same surgeon did a second procedure to remove the tumor. In this case, modifier 58 needs to be used because it’s apparent the surgeon was aware that the biopsy might result in a more extensive procedure.

Modifier 78 explained

The CMS states the following:

1. The subsequent procedure must take place in the operating room.
2. The second procedure must be related to the first.
3. The use of modifier 78 isn’t limited only to complications.

In conclusion, this modifier is to be used for related surgery that wasn’t planned at the time of the first procedure.

While this one is similar to the 58 version as they both cover procedures in the OR during post-op for a related procedure, modifier 78 is used when the doctor didn’t plan the second procedure until the first one ended.

For example, if a doctor performs a C-section and bleeding occurs that prompts the surgeon to call the patient back into the OR, it means the second procedure was unplanned. Since the same doctor will perform the surgery, it means that this modifier applies to this claim.

However, modifier 78 won’t apply if the procedure isn’t performed in the operating room.

Modifier 79 explained

Modifier 79 can be confusing too.

While it covers the procedures done in the post-op period by the same physician, modifier 79 is applied to unrelated procedures. To put it in another way, you shouldn’t worry about whether the procedure was planned or unplanned when there is no connection between the two operations. 

The best example of when you should use modifier 79 is when in a situation where a doctor performs exploratory surgery on a lump on a patient’s leg. The growth might turn out to be a benign cyst. Later on, if the patient returns to the same doctor during the post-op period to have another unrelated growth removed, it’s best to use modifier 79.

Modifier 24 explained

This one can be easily distinguished from other modifiers as it refers to unrelated E/M services performed by the same doctor post-op. If an E/M service is to be billed under this modifier there needs to be documentation proving that this service isn’t a part of the post-op.

For example, when a doctor performs surgery on a patient’s rotator cuff and afterward checks the patient’s knee pain, modifier 24 applies to the second E/M procedure.

Modifier 59 explained

While for some this modifier might cause confusion, it’s pretty simple to differentiate it from the other ones. Modifier 59 refers to a non-E/M service performed on the same day. In comparison, modifiers 79, 78, and 58 refer to unrelated procedures or E/M services performed post-op.

However, the point of confusion is usually regarding modifier 79. Both modifiers can refer to the same set of procedures that occur during the post-op period. 

This is because the phrase same day service can also refer to a post-op period because this period can technically start on the same day.

Still, for the same day non-E/M services, it’s recommended that you use modifier 59 as the phrase ‘’same day’’ is more specific. Additionally, if a different injury/body part from the first procedure was operated on in the same session, modifier 59 can also be applied. 

For example, if the same doctor removes a growth from a patient’s abdomen and performs a small injury on the patient’s toe in the same session.

Removing ambiguity from billing

Some modifiers are mixed up more often than others. For instance, modifier 79 is often confused with 59. The same goes for modifiers 78 and 58. It’s our hope that by adhering to this guide, you’ll be able to look past the ambiguity and know exactly which modifiers to apply.

Clearing up the mess with modifiers that seem to overlap with each other is not only going to make your life easier, but it will also stop you from royally messing up your billing procedures. 

As far as your employer is concerned, they will appreciate the fact that there are fewer denied claims, but more importantly – that the rates of reimbursement are what they should be.