Billing for mental health services can be tricky, especially when it comes to using modifiers. Modifiers are small two-character codes that tell insurance companies exactly what kind of service you provided. If you use them correctly, your claims get paid faster and without issues.
But if you make mistakes—like using the wrong modifier, forgetting documentation, or applying them when they aren’t needed—you could face denied claims, delays, or even audits.
In mental health, where sessions can involve multiple services, providers, or telehealth visits, knowing how to use modifiers properly is extra important.
The Most Common Modifiers in Mental Health Billing
Before diving into errors, it’s important to know the main modifiers used in mental health billing:
- Modifier 25: Significant, separately identifiable E/M service on the same day as another procedure or service
- Modifier 59: Distinct procedural service, used to show two services are separate and not bundled
- Modifier 95: Synchronous telemedicine service via real-time audio and video.
9 Errors in Using Modifiers for Mental Health Visits
Modifiers can boost claim accuracy or cause denials if misused. Here’s a breakdown of the most common mistakes in mental health billing and how to avoid them.
1. Overusing or Misusing Modifier 25
Modifier 25 should be used when a provider performs a significant, separately identifiable evaluation and management (E/M) service on the same day as another procedure (such as psychotherapy).
- Adding Modifier 25 to E/M codes when no other service is billed: Modifier 25 is only needed if an E/M service is performed in addition to another procedure on the same day. If you bill only an E/M code, don’t add Modifier 25.
- Using Modifier 25 without proper documentation: The E/M service must be significant and separately identifiable from the other service. If your notes don’t clearly show this, the claim may be denied or flagged for audit.
- Applying Modifier 25 to non-E/M codes: Modifier 25 is only for E/M codes (99202–99499), not for psychotherapy or procedure codes.
How to Avoid:
Document each service separately, clearly showing the need for both. Only use Modifier 25 when you provide a distinct E/M service in addition to another procedure on the same day.
2. Incorrect Use of Modifier 59
Modifier 59 is used to show that two procedures or services, normally bundled together, are actually separate and distinct when performed on the same day. Common Errors:
- Using Modifier 59 when another, more specific modifier is available: Modifier 59 is a “last resort” and should only be used when no other modifier fits. For example, if a more specific modifier (like XS, XE, XP, XU) is available, use that instead.
- Applying Modifier 59 to E/M services: Modifier 59 is not for E/M codes. It’s for procedures and therapies, such as when you provide both group and individual therapy on the same day.
- Lack of documentation: If you use Modifier 59, you must document why the services are distinct, such as different times, locations, or types of therapy.
- Overusing Modifier 59: Using Modifier 59 too often, especially without justification, can trigger audits and payment recoupments.
How to Avoid:
Only use Modifier 59 when services are truly separate, and document the distinction. Review payer guidelines for preferred modifiers.
3. Failing to Use Telehealth Modifiers
Modifier 95 is used for real-time, interactive telemedicine services.
- Not using Modifier 95 for telehealth visits: If you bill a telehealth session without the correct modifier, the claim may be denied or paid at a lower rate.
- Using Modifier 95 for non-telehealth services: Only use Modifier 95 for services delivered via real-time audio and video.
- Not checking payer-specific telehealth rules: Some payers may require other modifiers or place of service codes for telehealth.
How to Avoid:
Stay updated on telehealth billing rules for each payer. Use Modifier 95 only for real-time telehealth and document the modality in your notes.
4. Inconsistent or Unnecessary Modifier Use
- Adding modifiers when they aren’t needed: Overusing modifiers can complicate billing and raise red flags during audits.
- Inconsistent use among providers: If some providers use modifiers and others don’t for the same service, it can signal a billing problem.
- Using outdated or incorrect modifiers: Modifier codes and rules change. Using old codes can lead to denials.
How to Avoid:
Train staff regularly, use up-to-date coding resources, and implement a quality assurance process to review modifier use.
5. Incorrect Use of Multiple Modifiers
- Wrong order of modifiers: Some payers require credentialing modifiers first, then service modifiers. Incorrect order can cause denials.
- Missing required combinations: For example, a telehealth claim may need both a credentialing and a telehealth modifier.
- Duplicating modifiers: Never use the same modifier more than once on a claim.
How to Avoid:
Check payer-specific rules for modifier order and combinations. Use billing software with built-in checks for modifier use.
6. Lack of Supporting Documentation
- Failing to document why a modifier was used: Every modifier should be supported by clinical notes showing why the service was distinct, separate, or required a specific credential.
- Missing time documentation: For time-based codes, always document the start and end times to justify the code and modifier.
- Not updating documentation templates: Outdated templates may miss new documentation requirements for modifiers.
How to Avoid:
Use standardized documentation templates that prompt for all required details. Audit records regularly to ensure compliance.
7. Confusing Modifier 59 with Modifier 51
What’s the Difference between Modifier 59 and 51?
- Modifier 59: Used to show two services are distinct and not bundled.
- Modifier 51: Used to show multiple procedures in the same session.
Common Errors:
- Using Modifier 51 when 59 is needed (and vice versa): Each modifier has a specific use. Using the wrong one can cause denials or underpayments.
How to Avoid:
Understand the definitions and use cases for each modifier. If in doubt, consult payer guidelines or a coding expert.
8. Not Staying Updated on Modifier Rules
- Missing annual updates: CPT and HCPCS codes, as well as modifier rules, are updated every year. Using outdated rules can lead to denials.
- Ignoring payer-specific changes: Payers may change their modifier requirements at any time.
How to Avoid:
Subscribe to coding updates from CMS, AMA, and your major payers. Hold regular staff training sessions.
9. Using Modifiers to “Bypass” Edits or Increase Payment
- Adding modifiers just to get a claim paid: Using modifiers to override payer edits without proper justification is considered abuse or even fraud.
- Pattern of modifier misuse: Frequent incorrect use can trigger audits and repayment demands.
How to Avoid:
Only use modifiers when truly appropriate and always support them with documentation. Never use modifiers to “game” the system.
Best Practices to Prevent Modifier Errors
Accurate modifier use is critical for timely reimbursements. Follow these proven strategies to reduce denials, avoid audits, and ensure clean claim submissions.
Best practice to prevent modifier errors:
- Train Staff Regularly: Ongoing education is key to keeping up with modifier rules and payer requirements.
- Use Billing Software with Checks: Modern EHR and billing systems can flag missing or incorrect modifiers before submission.
- Audit Claims Before Submission: Pre-bill audits catch errors early and reduce denials.
- Stay Updated: Subscribe to coding and payer updates, and review changes annually.
- Document Everything: Every modifier must be backed by clear, detailed clinical notes.
- Communicate with Payers: If you’re unsure about a modifier, check with the payer before submitting the claim.
Conclusion
Modifier errors are one of the most common and preventable causes of claim denials and payment delays in mental health billing.
By understanding the most frequent mistakes, staying up-to-date on coding rules, and building strong documentation habits, your practice can avoid costly errors and maximize revenue. Remember: clean claims mean faster payments, fewer audits, and more time to focus on what matters most caring for your patients.
