[This post was originally published on 17th February 2022. It has been updated on 7th January 2026]
Chiropractic billing isn’t just about getting paid, it’s about getting paid correctly. With tighter payer scrutiny and evolving rules, even small coding or documentation mistakes can lead to denials, delayed payments, or audit headaches. To protect your revenue, every service you bill must be medically necessary, clearly documented, and performed by a licensed chiropractor, with the right CPT codes, diagnoses, and chiropractic modifiers supporting the care you provide.
Most Commonly Used Modifiers for Chiropractic Billing
1. Modifier AT – Active Treatment (Critical for Coverage)
What it means:
Modifier AT signals that spinal manipulative treatment (CPT 98940–98942) is active, corrective care rather than maintenance. This modifier is now required on Medicare claims for covered chiropractic manipulation services.
Best practices
- Append -AT to all spinal manipulation codes (98940–98942) that meet medical necessity criteria.
- Claims should include a primary diagnosis of subluxation and a secondary diagnosis that reflects the patient’s neuromusculoskeletal condition. The patient’s medical record should support the services you are billing.
- Ensure your documentation demonstrates active symptom relief and measurable clinical improvement (e.g., objective findings, functional goals).
- For non-covered or excluded services (e.g., many extraspinal or supportive modalities), modifier GY may be required instead.
Common Chiropractic AT Modifier Mistakes
- Using AT on maintenance care or continuing wellness treatments (these won’t be reimbursed and trigger denials).
- Forgetting AT when required, Medicare and many payers reject claims without it.
[Read: Ultimate Guide To Chiropractic Medical Billing & Coding]
2. Modifier 25 – Significant, Separately Identifiable E/M Service
What it means:
Modifier 25 is used only on Evaluation & Management (E/M) codes to indicate that the visit included a distinct E/M service separate from other procedures performed that day.
When a Chiropractic Manipulative Treatment (CMT) is performed and billed, the service already includes a brief pre-manipulation and post-manipulation patient assessment. These evaluative components are considered inherent to the CMT service and, on their own, do not qualify for separate E/M billing.
According to CPT guidelines, modifier 25 is appended to an Evaluation & Management (E/M) code to indicate that a significant, separately identifiable E/M service was performed in addition to the chiropractic manipulation on the same date of service. This modifier applies to both new and established patients.
When to use it
It is appropriate to bill both a CMT and an E/M service, with modifier 25 appended to the E/M code, when both services are truly performed and medically necessary during the same visit. Common scenarios include:
- New patient visit where a comprehensive evaluation is performed and an adjustment is also provided on the same day
- Established patient with a new condition, new injury, aggravation, or exacerbation, requiring a separate evaluation before deciding to adjust
- Periodic re-evaluation to determine whether a change in the treatment plan is needed, followed by treatment on the same visit
In each of these cases, the clinical decision-making, examination, and assessment must be distinct from the assessment normally included with CMT.
Documentation tips
- Modifier 25 is appended only to the E/M code (e.g., 99202–99205, 99212–99215), not to the CMT codes (98940–98943)
- Both the E/M service and the CMT must be performed on the same visit
- If only an E/M service is billed (with no manipulation), modifier 25 is not required
Documentation must clearly demonstrate:
- Why the additional evaluation was necessary
- What was assessed beyond the routine CMT evaluation
- How the findings influenced clinical decision-making or changes to the care plan
Common chiropractic coding modifier mistakes to avoid
- Automatically appending modifier 25 at every visit
- Billing an E/M service when only a routine pre-adjustment assessment was performed
- Failing to document a new condition, exacerbation, or treatment plan change
- Applying modifier 25 to the CMT code instead of the E/M code
3. Modifier 59 & X-Series Modifiers – Distinct Procedural Services
59 and the X-series (XE, XP, XS, XU) chiropractic CPT modifiers are used to indicate that two non-E/M services performed on the same date of service are separate and distinct, even though they would normally be bundled under National Correct Coding Initiative (NCCI) edits.
According to CPT and CMS guidance, these modifier codes in medical billing should be used only when clinical circumstances clearly justify separate billing and when documentation supports that distinction.
Key rule:
Always use the most specific X-modifier available. Modifier 59 should be used only when no other X-modifier accurately describes the situation.
Critical Compliance Rules
- Never use modifier 59 or X-modifiers on E/M services
(Use modifier 25 for separate E/M services instead.) - Do not use these modifiers simply to bypass NCCI edits
- Different diagnoses alone do NOT justify these modifiers
- Medical documentation must support the reason for separation
Improper use is a common trigger for claim denials, recoupments, and audits.
Appropriate Uses in Chiropractic & Therapy Settings
1. Separate Anatomic Sites (XS or 59)
Use XS (preferred) or 59 only when procedures are performed on:
- Different organs
- Different anatomic regions
- Non-contiguous lesions in different regions of the same organ (limited situations)
Do not use these modifiers when treating:
- Contiguous structures in the same region
- Adjacent tissues considered a single anatomic site
Example (Not Separate):
- Treating the nail, nail bed, and surrounding tissue of the same finger = one anatomic site
2. Separate Encounters on the Same Day (XE or 59)
Use XE when:
- Two procedures are performed during distinct patient encounters on the same date
- No other modifier (24, 25, 27, 57, 58, 78, 79, 91) more accurately applies
This is common when a patient returns later the same day for an unrelated service.
3. Timed Services Performed Sequentially (XE or 59)
Modifier 59 or XE may be used only for timed codes when:
- One service is fully completed
- The second service begins after the first ends
- Services are not intermingled
This applies only to codes defined by time units (e.g., per 15 minutes).
4. Diagnostic Services Before Therapeutic Procedures (XU or 59)
A diagnostic procedure may be billed separately only if:
- It occurs before the therapeutic service
- It directly informs the decision to perform the therapeutic procedure
- It is not an inherent part of the therapeutic service
If the diagnostic work is normally included in the procedure, do not bill it separately.
5. Diagnostic Services After Therapeutic Procedures (XU or 59)
A diagnostic procedure performed after treatment may be billed separately only when it:
- Occurs after the therapeutic service is completed
- Is not a routine or expected follow-up
- Is not required as part of post-procedure care
Documentation Best Practices
Your clinical notes must clearly show:
- Why services were separate
- Where they were performed (site/structure)
- When they occurred (separate encounter or time block)
- How they did not overlap clinically
Strong documentation is the only defense against denials and audits when using these modifiers.
Common Chiropractic Billing Modifier Errors to Avoid
- Using modifier 59 or XU simply because two CPT codes have different descriptions
- Appending modifiers when services occur at the same site, same encounter, and overlap clinically
- Applying modifiers without clear, detailed documentation
- Treating different diagnoses as justification for separate billing
- CPT and CMS state that codes remain bundled unless one of the specific separation criteria is met.
6. Modifiers RT & LT – Side-Specific Location Identifiers
What they do:
Modifiers RT (right) and LT (left) tell the payer which anatomical side was treated. They are commonly used with orthotic or brace codes and joint-specific procedures that can occur on either side.
- Reporting two units of a bilateral code without side modifiers will often be denied or down-coded.
- Proper side modifiers (RT/LT) clarify that services were provided separately to each side.
Examples
- For custom orthotics, include L3020-RT and L3020-LT rather than two units of L3020 alone.
Avoiding Denials & Audits
Make sure to avoid these mistakes when using modifiers in chiropractic billing:
- Maintain complete clinical documentation that reflects medical necessity, diagnosis linkage, and rationale for distinct procedures.
- Regularly update billing staff on payer-specific rules, as insurers interpret modifiers differently.
Use internal audits and billing software to flag missing modifiers before submission.
Conclusion
Accurate use of modifiers for chiropractic billing like AT, 25, 59/X-modifiers, and RT/LT is no longer optional, it’s essential for clean claims and optimized revenue. Misuse or omission leads to denials, delayed payments, and potential audit exposure.
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Related Articles:
5 Chiropractic Medical Billing Strategies To Boost Your Monthly Revenue
Know The Top Chiropractic CPT Codes That Can Save Your Billing Time
In-House Chiropractic Billing Or Outsource It – That’s A Million Dollar Question!
