Modifier 24 and Its Wound Care Coding Uses

As a wound care provider, you’re probably very familiar with classifying wounds and making treatment recommendations. However, something that occasionally stumps even the best practitioners is medical billing codes. For one, it’s not always clear when or how often you should use them. Then, when you finally figure it out, sometimes, they’ve been updated again. On top of that, there are different structures and modifiers that add another level of confusion. 

One particular code that often perplexes wound care specialists is modifier 24. Incorrect use of this modifier can lead to billing errors, which may cause denied claims, delayed payments, and stress. If you’d like to get up to speed on this modifier and understand truly “what is modifier 24?”, when it should be used, and more, keep reading.

Understanding CPT Codes and Their Connection to Modifier 24

Before we define what modifier 24 is specifically, it’s important to clarify where the number “24” actually comes from. 

Used in medical billing, modifier 24 is considered a part of the Current Procedural Terminology (CPT) system. Currently, the CPT system is the most accepted medical nomenclature for services provided. 

The American Medical Association (AMA) created the CPT code to make things simple and consistent for payers, institutions, and more to identify the services healthcare professionals provide. These codes also serve as a way to monitor healthcare use, determine reimbursements, and obtain statistical information on different populations.  

However, modifier 24 isn’t a true actually a CPT code. CPT codes are five digits long and are used to inform what procedure or medical service was provided for a patient. So a CPT code like 97597, which is categorized under active wound management, means that a debridement method was performed on a wound that’s 20 square centimeters or less. 

CPT modifiers, like modifier 24, are only two digits and may be numeric or alphanumeric. However, they’re typically the latter. Modifiers tell the insurer more information about the service or procedure, such as if multiple procedures were completed, why that procedure was needed, the number of surgeons aiding the patient, and more. It’s not intended to alter or replace the main CPT code, but to call attention to special circumstances linked with the service or procedure that the patient received.  You’ll typically find modifiers added with a hyphen at the end of the CPT code. 

So, What Is Modifier 24? 

Now that we’ve clarified where modifiers stem from, let’s quickly define what modifier 24 is all about. 

According to the American Academy of Professional Coders (AAPC), this modifier is defined as “Unrelated evaluation and management service by the same physician or other qualified health care professional during a postoperative period.” 

When Should Modifier 24 Be Used?

To help you better understand when this modifier should be used, let’s break down some keywords mentioned in that previous definition. 

Let’s start with “evaluation and management” (E/M). These codes describe services that involve, as the name suggests, evaluating and managing a patient’s health. E/M services can include many things, such as preventive medicine, an outpatient visit, or home services. However, they don’t include things like surgery, which fall under the procedure code category. 

Next, let’s look at the term “unrelated” and what that may communicate. 

Surgical procedures have an associated global period, meaning there’s a period of time, usually zero, 10, or 90 days, surrounding the surgery, where certain services and supplies are expected to be performed and used. This timeframe includes pre-operative services, the actual procedure itself, and post-operative care. Because these things are expected, the associated expenses are already bundled into the global surgery fee. 

As a result, they’re not eligible for separate reimbursement and will be denied if billed within the global period of the associated surgical procedure. 

In a scenario where treatment is performed, and it’s not a typical or routine part of recovery, and thus unrelated, that’s when modifier 24 might be appended. 

But What’s Considered Normal Post-Operative Care?

Standard postoperative care during the global period may include: 

• Speaking with the patient and their family.
• Coordinating the patient’s care.
• Follow-up office and hospital visits related to recovery.
• Post-surgical pain management (e.g., prescribing medications).
• Writing orders.
• Supplies.
• Cutaneous suture and staple removal.
• The removal of tubes, wires, casts, etc. 
• Insertion, irrigation, and removal of intravenous lines, catheters, etc. 
• Dressing changes and local incision care.

What about Wound-Related Postoperative Complications? 

Let’s say a wound-related procedure, such as an incision, amputation, or drainage service, was performed. These procedures usually have a 10- to 90-day postoperative global period, during which most payers will cover any care provided, which means services shouldn’t be separately submitted for billing. There are, however, some exceptions. 

If a complication related to the wound-related procedure occurs during the global period and an E/M service is completed, no available modifier allows payment for that E/M.

However, different insurance companies have different rules. For instance, a payer like Medicare may not pay for a post-operative wound complications during the global period unless the patient has a related but unplanned procedure. If the patient has to return to the operating room, endoscopy suite, or cath lab to treat a wound infection, then the 78 modifier may be appended. However, if an unrelated procedure is performed outside of the operating room during the global period of the original procedure, modifier 79 may be used. 

Currently, the only E/M modifier that can be used during the postoperative period is the 24 modifier. Plus, as we previously mentioned, it’s only justified when it’s for an issue unrelated to the one in which that patient is in the global period. Therefore, if a patient visits their surgeon during the post-operative stage and has a wound infection, that E/M visit shouldn’t be billed separately since it’s already in the global package. 

Bonus tip: Modifier 79 and modifier 24 often confuse people, but represent an unrelated surgical procedure and an unrelated E/M service, respectively. 

The Correct Use of Modifier 24 

We understand that grasping the proper use of modifier 24, and proper coding in general, is no easy feat, especially given all the other demands of your day-to-day tasks. To help you along, here are some tips you can quickly reference.

• Modifier 24 should only be appended to E/M codes
• Utilize this modifier only to report an E/M service beginning the day after a procedure completed by the same physician during the past 10 or 90 postoperative days
• Ensure the documentation records that the service was exclusively for treating an underlying condition and not for post-operative care
• Qualified health professionals managing immunosuppressant therapy during the post-operative period of a transplant can append modifier 24
• Modifier 24 can be applied to physicians managing chemotherapy during the postoperative period of a procedure

Examples of Proper Modifier 24 Use

Now, let’s look at a few examples. 

Five days ago, a 27-year-old patient came in to have an intermediate repair of a 25-centimeter superficial wound to the right hand (the CPT code used is 12046). They entered their physician’s office today with a stuffy nose and facial pressure. The physician completes a history and examination and diagnoses them with sinusitis. They prescribe antibiotics, a leukotriene inhibitor, and a decongestant. 

In this example, the CPT code 99213-24 is assigned for the office outpatient visit of an established patient. Accurate documentation showcases that a detailed history, an expanded physical examination of the patient’s primary complaint, and low-complexity medical decision-making took place. 

In another case, a 52-year-old-patient has left ear surgery, and during the postoperative period, they experience pain, redness, and swelling on the right leg. The physician determined that it was a skin infection, but it was unrelated to the surgery. As a result, the appropriate E/M service for treating the issue should be billed using modifier 24. 

In yet another situation, Sarah, who has type 2 diabetes, went back to her OB/GYN’s office with surgical wound dehiscence about three weeks following delivery via cesarean section. The physician completed an E/M and assessed the wound. Following the evaluation, Sarah’s doctor determined they needed to make an incision and complete drainage to ensure that Sarah healed adequately. 

In addition, the physician instructed Sarah on proper wound care, reviewed her blood sugar numbers, and prescribed an antibiotic. A detailed history was recorded in the EHR, along with an expanded problem-focused exam and medical decision-making of moderate complexity. 

This encounter can include both the 24 and 79 modifiers since they’re unrelated to the c-section. The delivery of Sarah’s baby created the global period, but this was unrelated to the care she received for her diabetes and the obstetric surgical wound. The “unrelated” is upheld by the surgical complication diagnosis, which is not the diagnosis associated with the surgery.

The Incorrect Use of Modifier 24 

At this point, you might have a pretty good idea of when and how to use the 24 modifier. However, we still want to provide a quick reference to assess when not to use it. 

You should not utilize modifier 24 when: 

• The E/M is for removing sutures, an infection or surgical complication, or other wound treatment, as they’re a part of the surgery package.
• The documentation clearly suggests that the E/M is related to the procedure.
• It’s outside of the postoperative period of a procedure.
• The services are provided on the same day as the procedure.
• You’re completing routine postoperative care.
• Reporting surgical procedures, labs, x-rays, or supply codes.
• A surgeon admits a patient to a skilled nursing facility for a condition related to the procedure.

What Practitioners Should Know About Modifier 24

As a practitioner, it’s essential to understand that every insurance company has its own rules for processing claims with modifiers. After sending a claim in, it’s possible that the payer may deny it or request additional proof showcasing that the service was unrelated. Some of them may even pay the claim and then request evidence at a later date. You may have to provide a refund if they don’t believe the modifier qualifies. 

Another thing to keep in mind is that all providers in the same clinic or specialty are deemed the same provider. When reading coding rules, it’s common to see verbiage like “the same physician is managing XYZ.” However, if provider A at the practice completed the surgery, and provider B at the same practice performed the follow-up, the modifier could still be used.  

The Difference Between Modifier 24 vs 25

Remember we mentioned that modifier 24 couldn’t be appended if the E/M service was performed on the same day as the procedure? Well, if you see and manage a patient for a separately identifiable reason on the same day as a procedure, modifier 25 might be appropriate. The main difference between modifiers 24 and 25 is when the “unrelated” service was performed. 

A coder might apply this if the E/M service goes beyond the standard preparation and follow-up care involved with the procedure. 

For example, Bob, an established patient, presents with a growing lesion on the nose. He also complains of multiple growths that are increasing in size on his back and dense, scaly lesions on his bald scalp. To check for basal cell carcinoma, you biopsy the nose lesion using a shave technique. 

You also determined that his back lesions are seborrheic keratoses, so treatment isn’t needed. However, Bob was diagnosed with diffuse scalp actinic keratoses and prescribed topical 5-fluorouracil cream. You discussed the treatment plan with him to ensure he understood. 

Coding in this scenario may look like this.

• Code 11102: Tangential biopsy of skin
• Code 99213: An established patient office visit that involves a low level of medical decision-making and/or lasts between 20 and 29 minutes.
• Modifier 25: This may be appended to explain that a significant, separately identifiable E/M service was performed. 

While the E/M service connected with the suspected basal cell carcinoma is included in the global package for the skin biopsy code, managing the growths and scalp legion can be reported as a separate E/M service. 

Properly Documenting Modifier 24 Is Key

As a wound care specialist, your goal is to achieve the best outcome for your patients. However, you also deserve to be adequately compensated for doing so. Many clinicians miss out on modifier 24 and others because they’re not really sure how to use them. 

We hope this overview serves as a helpful guide for maximizing reimbursements while providing excellent patient care.