In May 2025, a Connecticut psychiatrist and her practice paid $427,129.11 to settle allegations with the federal government over improper billing. The issue? Misuse of Modifier 25 on evaluation and management services claims submitted to Medicare between April 2017 and November 2019.

This isn’t an isolated incident. Across every medical specialty, modifier errors drain revenue and trigger audits. In EP and interventional procedures, where coding complexity is at its peak, these mistakes occur more frequently than most practices realize.

Let’s explore the most common modifier errors in EP and interventional procedures and how to prevent them before they cost you.

What Are Modifiers in Medical Coding?

Modifiers are two-digit codes. They give extra details about a service. They tell the payer that a procedure was changed, but not stopped.

In EP and interventional cases, modifiers help explain:

  • Separate services
  • Multiple procedures
  • Professional vs technical work
  • Distinct sessions or sites

Correct modifier use supports clean claims.

Why Modifier Errors Happen in EP & Interventional Procedures

Modifier errors occur for many reasons. EP and interventional coding are detailed and time-based. Small mistakes can cause big issues.

Common Causes

  • Complex procedure bundling
  • Poor note review
  • Lack of modifier rules
  • Copy-paste coding habits
  • Outdated payer guidance

These factors raise the risk of modifier misuse.

Common Modifier Errors

1. Using Modifier 59 Incorrectly

Modifier 59 is often used to bypass bundling edits. However, it should only apply when two services are truly separate. In EP and interventional work, it’s best to verify if another modifier (XE, XS, XP, XU) better describes the case.

2. Missing 26 and TC Components

In cardiac imaging and EP studies, billing both the technical and professional parts separately is common. Forgetting to add Modifier 26 or TC can cause denials or duplicate claims.

3. Confusion with Modifier 25

Modifier 25 should only be used when a distinct E/M service is provided on the same day as a procedure. Many claims are flagged because this modifier is added even when no separate E/M work was done.

4. Incorrect Repeat Procedure Modifiers

Modifiers 76 and 77 show repeat procedures. Not choosing the correct one—same provider vs. different provider—can lead to overpayment or claim rejection.

Building a Culture of Accuracy

Coding accuracy isn’t just a billing department goal. It’s a practice-wide commitment that protects your revenue and reputation. 

Make Quality Everyone’s Job

Coding accuracy isn’t just the billing department’s responsibility. Physicians, nurses, and administrators all play roles.

Physicians should:

  • Complete documentation promptly
  • Include specific anatomical details
  • Note unusual circumstances

Billing staff should:

  • Code accurately based on documentation
  • Query physicians when records are unclear
  • Stay current on payer policies

Administrators should:

  • Provide adequate training resources
  • Support time for quality reviews
  • Address systemic documentation problems

Learn From Mistakes

When errors occur, avoid blame. Instead ask:

  • What gap in knowledge led to this?
  • Does this error pattern suggest a training need?
  • Would a process change prevent recurrence?

Use mistakes as learning opportunities that strengthen your entire operation.

Conclusion

MDaudit’s recent data from 1.2 million providers reveals that coding errors cause 25% of audit requests in hospitals and 10% in professional settings. The average at-risk amount for hospital audits is around $17,000. Practices that perform EP and interventional procedures can add up rapidly. The good news is that these errors are entirely preventable with proper review, clear notes, and updated knowledge.

Clean modifier use leads to faster payments, fewer denials, and stronger compliance. Focus on accuracy, not speed, and results will follow.

Contact Maryland Medical Billing to eliminate modifier errors for good. We specialize in accurate EP and interventional procedure coding that protects your revenue and keeps you compliant.

FAQs

What modifier to use when a procedure is unsuccessful?

Modifier 53 may also apply if the provider must stop a procedure due to equipment failure or other extenuating circumstances (for example, the provider injures themselves while performing the procedure).

When to use 25 and 59 modifiers?

Use Modifier 25 for a significant, separately identifiable Evaluation & Management (E/M) service (like an office visit) performed on the same day as a procedure; use Modifier 59 for distinct, non-E/M procedures (like a biopsy or therapy).

What are common modifier 59 errors?

Here are some common errors: Overusing It: Don’t use Modifier 59 if another modifier, like XE or XS, fits better. Lack of Documentation: Failing to explain why Modifier 59 was necessary. Unbundling Procedures: Separating procedures that should be billed as one service

An Easy Guide for Providers

Get in Touch