Chiropractic Modifiers Explained: 25, 59, AT (2026 Edition)

Chiropractic Modifiers Explained: 25, 59, AT (2026 Edition)

Chiropractic billing in 2026 requires careful and accurate use of modifiers—especially 25, 59, and AT. These modifiers signal important details about services delivered, and incorrect usage is one of the most common causes of denials and chiropractic audits. Understanding when and how to use each modifier is essential for clean claims, strong documentation, and payer compliance.

This guide explains how chiropractic modifiers 25, 59, and AT function, what payers expect, and how to document appropriately to prevent claim reviews or audits.

Why Modifier Accuracy Matters in 2026

Payers, including Medicare, are using more automation to detect inconsistencies between documentation, diagnosis, and modifier use. Improper use of modifiers is often interpreted as overbilling or incorrect reporting, even when the mistake was unintentional. For chiropractors, modifier errors frequently result in:

• Claim denials
• Record requests
• Post-payment audits
• Delayed reimbursement

Applying the correct modifier with strong documentation is the simplest way to reduce risk.

Modifier AT: Active Treatment

The AT modifier indicates that chiropractic manipulation is part of active treatment for a neuromusculoskeletal condition. Medicare requires this modifier for spinal CMT codes (98940–98942) when treatment is intended to improve function, not maintain it.

Key Points About AT Modifier Usage

• Required for active treatment under Medicare.
• Must not be used for maintenance care.
• Documentation must demonstrate functional improvement or treatment aimed at improvement.
• Assessment and plan should show measurable goals.

CMS defines maintenance care as care that seeks only to prevent deterioration, which is not covered. AT incorrectly applied to maintenance care is a major audit trigger.

What Documentation Must Support AT?

• Initial exam with diagnosis and functional deficits.
• Treatment plan with goals and re-evaluations.
• Ongoing notes showing progress or rationale for continued care.

Modifier 25: Significant, Separately Identifiable E/M Service

Modifier 25 is appended to an evaluation and management (E/M) service performed on the same day as a chiropractic adjustment. The modifier tells payers that the E/M was above and beyond the pre-adjustment assessment normally included in CMT codes.

When Modifier 25 May Be Appropriate

• The patient presents with a new complaint requiring separate evaluation.
• A significant change in condition requires a full reassessment.
• An E/M service is necessary to determine the need for a new or revised treatment plan.

Documentation Requirements for Modifier 25

Documentation must clearly show:

• The E/M elements performed
• Why the evaluation was medically necessary
• How it differs from the pre-service evaluation associated with CMT

Payers frequently deny 25-modifier claims when documentation does not justify a distinct E/M service.

Modifier 59: Distinct Procedural Service

Modifier 59 is used to indicate that two procedures are distinct from one another, even if they might otherwise be considered part of the same encounter. Chiropractors most commonly use modifier 59 with therapy services when they are separate and distinct from manipulation.

Appropriate Uses of Modifier 59

• Separate anatomical region
• Separate session
• Different purpose or distinct therapeutic service

Payers require documentation showing why the therapy service was separate from manipulation and not bundled.

Documentation Requirements for Modifier 59

• Clear rationale for the therapy service
• Evidence of a distinct region or purpose
• Time documentation for time-based therapy codes
• Objective findings justifying both services

Incorrect use of modifier 59 is closely monitored by payers and is a common cause of audits.

How to Avoid Modifier-Related Denials and Audits

1. Document the Medical Necessity of Each Service

• Include functional deficits and goals
• Describe patient response to treatment
• Update plans of care when appropriate

2. Match Diagnoses to Services

ICD–CPT alignment must be clear and logical.

3. Avoid Routine or Automatic Modifier Use

Modifiers must reflect clinical reality — not habit or billing workflow.

4. Train Staff and Providers Regularly

Modifier misuse is often a training issue, not intentional error.

5. Conduct Monthly Internal Audits

Review modifier usage patterns and documentation quality.

FAQ: Chiropractic Modifiers in 2026

Is modifier AT ever used on non-spinal manipulation?

No. Medicare applies the AT modifier requirement only to spinal manipulation codes 98940–98942.

Does modifier 25 require a separate diagnosis?

No, but documentation must show a separately identifiable E/M service that is not part of the CMT pre-service work.

Can modifier 59 be used with 97140?

Yes, when manual therapy is distinct and performed on a different region from the manipulation.

Do commercial payers follow the same modifier rules as Medicare?

Many do, but payer policies vary. Always check the payer’s medical policy.

Conclusion

Correct use of modifiers 25, 59, and AT is essential for chiropractic billing accuracy in 2026. These modifiers communicate critical clinical information to payers, and misuse can lead to denials, record requests, or audits. With clear documentation, careful application, and periodic internal audits, chiropractors can significantly reduce modifier-related billing risk.

References

• Centers for Medicare & Medicaid Services (CMS). Medicare Benefit Policy Manual.
• CMS Program Integrity Manual.
• American Chiropractic Association (ACA) Documentation & Billing Resources.
• Payer Medical Policies for Chiropractic Services (2026).