The “Big 3” Reasons Your Dermatology Claims Are Denied
While a denial can be triggered by simple demographic errors, the persistent, high-volume rejections in dermatology almost always trace back to technical coding mistakes in three specific areas: Mohs surgery, complex repairs and excisions, and modifier misuse. Understanding these challenges is the first step to solving them.
Challenge #1: The Intricate Layers of Mohs Surgery Coding
Mohs micrographic surgery is one of the most effective treatments for skin cancer, but it’s also one of the most complex procedures to code correctly. The codes (CPT 17311-17315) are based on stages and the number of tissue blocks, creating multiple opportunities for error. The most common mistake isn’t in coding the Mohs procedure itself, but in billing for the subsequent repair. Payers have strict rules about what is bundled into the primary procedure. For example, a simple repair is almost always considered part of the Mohs package. If you bill for a complex repair without meticulous documentation justifying its medical necessity, you’re inviting an instant denial. A Common Denial Scenario:
- Incorrect Billing: The surgeon performs a two-stage Mohs procedure on a patient’s cheek (CPT 17311 for the first stage, 17312 for the second). They then perform an intermediate repair. The claim is submitted with all three codes.
- The Result: The claim is denied because the documentation didn’t sufficiently prove the repair was more complex than a standard closure, which is bundled into the Mohs fee.
- The Fix: This requires a deep understanding of payer-specific guidelines. A certified dermatology coder knows to check the NCCI edits and ensure the surgeon’s notes clearly differentiate the repair as a distinct and separate procedure, justifying its separate billing.
Challenge #2: Navigating the Ambiguity of Excisions and Repairs
The difference between a simple, intermediate, and complex repair might seem clear in a textbook, but in practice, it’s a gray area that causes countless denials and downcodes. The key isn’t just the procedure itself, but the level of detail in the provider’s documentation.
- Simple Repair (e.g., CPT 12001-12021): A single-layer closure. This is often bundled with the primary excision code.
- Intermediate Repair (e.g., CPT 12031-12057): Requires a layered closure of subcutaneous tissue and skin.
- Complex Repair (e.g., CPT 13100-13160): Involves more than a layered closure, such as debridement, extensive undermining, or retention sutures.
The most frequent revenue leak is under-coding a complex repair. A provider may perform a procedure that meets the criteria for a complex repair, but if the operative notes only mention a “layered closure,” it will only support a code for an intermediate repair. The financial difference can be substantial, and consistently getting this wrong leaves significant revenue on the table.
Challenge #3: Misusing Modifiers – The #1 Source of Revenue Leaks
If there’s one area that separates expert dermatology coders from the rest, it’s the masterful use of modifiers. Two modifiers, in particular, are responsible for a huge percentage of dermatology denials when used incorrectly: Modifier 25 and Modifier 59.
Modifier 25: The Same-Day E/M Service
Modifier 25 is used to indicate a “significant, separately identifiable Evaluation and Management (E/M) service by the same physician on the same day of the procedure or other service.”
- When to Use It: A patient comes in for a scheduled skin cancer screening (the E/M service). During the exam, the dermatologist identifies a suspicious lesion and decides to perform a biopsy immediately (the procedure). Modifier 25 is appended to the E/M code to show that the initial consultation was separate from the decision to perform the biopsy.
- When Not to Use It (and Trigger a Denial): A patient comes in specifically for a scheduled mole removal. The brief pre-procedure check-up is not a “separately identifiable” E/M service—it’s part of the standard pre-operative work for the procedure. Appending Modifier 25 here is a classic error that payers flag immediately.
Modifier 59: The Distinct Procedural Service
Modifier 59 signals that a procedure was “distinct or independent from other non-E/M services performed on the same day.” It’s often used to unbundle codes that are typically packaged together. Because of its power, it’s one of the most scrutinized modifiers by payers.
- When to Use It: A dermatologist performs a biopsy on a lesion on the patient’s back and, in the same visit, destroys a pre-cancerous actinic keratosis on the patient’s face. Since these are different lesions on different anatomical sites, Modifier 59 can be used on the second procedure code to prevent the payer from bundling them.
- When Not to Use It: The dermatologist removes two separate but adjacent lesions through a single incision. Even though two lesions were treated, it was part of one procedure at one anatomical site. Using Modifier 59 here would be incorrect and lead to a denial.
From Denial Management to Denial Prevention
Dealing with these challenges one by one is exhausting and inefficient. It leaves your staff chasing down lost payments instead of focusing on patient care. The only sustainable solution is to prevent these errors from happening in the first place. This requires more than just good billing software; it requires a team that lives and breathes the nuances of dermatologic care. At DCBC, our certified coders are trained exclusively in this specialty. They don’t just process claims; they scrutinize documentation, ensure correct modifier application, and stay current on the latest payer rules and coding updates. This is the core of our medical coding expertise. By partnering with a team that understands the difference between a Mohs repair and a complex excision, you’re not just outsourcing a task. You’re investing in a proactive strategy that stops denials before they start, strengthens your revenue cycle, and provides peace of mind. Our approach is designed to transform your billing from a source of stress into a seamless, optimized part of your practice through dedicated denial management services.
Frequently Asked Questions
Why is dermatology coding so much more complex than other specialties?
Dermatology involves a high volume of in-office procedures with subtle variations. Unlike a specialty where a patient visit might result in a single E/M code, a single dermatology visit can involve an E/M service, a biopsy, a destruction, and a complex repair – all of which have overlapping rules and bundling edits that must be navigated correctly.
My EMR software suggests codes. Isn’t that enough?
EMR coding suggestions are a helpful starting point, but they are not a substitute for expert oversight. An EMR cannot interpret the nuances of a provider’s notes, understand the specific documentation required to justify a complex repair, or stay updated on the ever-changing rules of hundreds of different insurance payers. Over-reliance on EMR suggestions without expert validation is a common cause of denials.
We have an in-house biller. Why are we still seeing so many denials?
An excellent in-house biller who is a generalist may do a fantastic job with 90% of claims but still struggle with the unique 10% specific to dermatology. Without daily, dedicated exposure to Mohs surgery, complex repairs, and multi-procedure visits, it’s nearly impossible to achieve the level of expertise needed to bring denial rates down to the 5-10% industry average.
Secure Your Practice’s Financial Health
Stop letting complex coding rules dictate your practice’s profitability. By addressing the root causes of denials, you can protect your revenue, reduce administrative burdens, and focus on what you do best: providing exceptional patient care. If you’re ready to see how specialized expertise can transform your revenue cycle, let’s talk. Contact us for a consultation, and we’ll show you how a partnership with DCBC can make a difference.