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By Chermanda Jackson, Medical Coding & Compliance Auditor
November 25, 2025
Key Takeaways: Modifier misuse ranks among the top causes of claim denials, with modifiers 25 and 59 frequently confused despite serving distinct purposes—modifier 25 for separate E/M services and modifier 59 for distinct procedural services performed on the same day. Continue reading to learn about when to apply each modifier, common misuse scenarios that trigger payer audits, and how autonomous medical coding solutions eliminate modifier confusion while generating comprehensive documentation that supports every code assignment during audits and appeals.
CPT modifier 25 allows medical professionals to report separate evaluation and management (E/M) services that they perform on the same day as another service. The other service can be a significantly different E/M service or a procedure (1).
To be able to use modifier 25, the separate E/M service has to go above and beyond the work that you might typically associate with the original procedure or service (2). If the work the medical professional performed was typical for the procedure or service they’re already billing for, there is no need to use modifier 25.
Here are a few questions medical staff can ask themselves to help determine whether it’s appropriate to use modifier 25 under the E/M coding guidelines:
You don’t need to reach a separate diagnosis or use two different diagnosis codes to use modifier 25 (3). However, whether the medical provider reaches the same diagnosis or no diagnosis at all, the evaluation and management work must be separate from the procedure or service the patient came in for to justify the use of modifier 25.
By contrast, CPT modifier 59 applies when a medical professional provides two distinct procedural services on the same day that wouldn’t typically be grouped together but should be under the circumstances (4).
The Current Procedural Terminology (CPT) from the AMA states that you should only use modifier 59 if there are no other established modifiers that could be appropriate. If there aren’t any other more descriptive modifiers available and modifier 59 applies, only then use modifier 59 (4).
There are a few circumstances under which it makes sense to use Modifier 59 (5):
Check the National Correct Coding Initiative (NCCI) before applying modifier 59 to make sure the edits do not prohibit doing so.
The most obvious difference between modifier 25 vs. 59 is that modifier 25 deals with separate E/M services, while modifier 59 deals with non-E/M services or procedures (6). So, the first question to ask before using either of these modifiers is: Are you billing for E/M services or not?
Only use CPT modifier 25 if the medical professional provided separate E/M services on the same day as other services or procedures. Only use CPT modifier 59 if the medical professional completed a separate non-E/M service or procedure on the same day as another. Never add modifier 59 to E/M services.
Professionals can end up misusing modifiers 25 or 59 by billing a service or procedure as “separate” when it’s actually part of the standard work associated with the patient's visit. For example, if a patient comes in for a colonoscopy and the provider checks in before the procedure to make sure it’s still necessary, those evaluation services are part of the standard pre-procedure care. The provider cannot bill those services separately from the colonoscopy using modifier 25.
Another misuse scenario that comes up often is using modifier 59 when another modifier, such as XS (separate structure), is more appropriate. If the procedure is distinct because the medical provider performed it on a separate organ or structure in the patient’s body, that sounds like a scenario in which modifier 59 would apply. However, modifier XS is the more specific modifier, so it’s the one coders should use (4).
It’s worth noting that insurance payers closely monitor high use of modifiers like 25 and 59. Frequently using these modifiers could get your claims flagged for additional review or denial. Make sure you have clear, complete documentation of all the services provided and procedures performed and clinical justification for all of them. Documentation is your strongest resource when dealing with audits or compliance issues.
Apply these tips to ensure your charts meet compliance standards and help avoid auditing concerns:
Coding requirements change frequently. Staying on top of these changes can create significant administrative hassles for healthcare providers, leaving them with less time to focus on patient care. But failing to use the right codes creates compliance risks and increases the chances of costly claims denials.
The solution is using an automated coding engine to support medical coding team members.
With Nym’s coding engine, charts go into the engine and get coded automatically before heading directly to the billing department. There’s no human intervention required. Nym also automatically generates traceable documentation justifying every code it assigns. You have access to comprehensive, transparent resources backing up your codes in case you need them for audits or denials in the future.
Chermanda Jackson is a Medical Coding & Compliance Auditor at Nym. As part of the Coding and Compliance team at Nym, Chermanda works closely with both our customers and internal teams to ensure that Nym's autonomous medical coding engine is aligned with customer-specific internal guidelines, as well as external regulatory guidelines. Chermanda has over 20 years of experience in medical coding and auditing and joined Nym in early 2023.
