Did you know that according to the World Health Organization (WHO), globally, over 15 million people were living with spinal cord injury (SCI) in 2024?
It is one of the most prevalent health conditions worldwide, often caused by age, vehicle accidents, or other unforeseen reasons.
Healthcare providers recommend medications, treatments, and techniques to manage the resulting symptoms from such incidents. One such commonly performed technique is chiropractic spinal manipulation.
When billed to Medicare as active treatment, it requires the AT modifier. However, from a billing perspective, the staff must understand when this modifier is required.
AT Modifier – Description
The HCPCS Modifier AT, described as “Acute Treatment”, identifies active or corrective treatment. The Centers for Medicare & Medicaid Services (CMS) guidance describes the modifier in detail as active or corrective care.
It is a chiropractic-specific modifier applicable to three specific spinal manipulation codes:
- 98940 (one to two spinal regions)
- 98941 (three to four spinal regions)
- 98942 (five spinal regions)
Medicare’s regional Medicare Administrative Contractors (MACs), such as Noridian, mention that the modifier must be reported in specific situations.
The AT modifier indicates that the spinal manipulation performed was intended to correct a documented spinal subluxation and produce measurable functional improvement. Therefore, it is not meant to maintain a patient’s current status.
Note that modifier AT is not required for extraspinal manipulation (CPT 98943) because Medicare does not cover this service, regardless of the documentation.
Scenarios Where the AT Modifier is Applicable
Although the AT modifier is used frequently in medical billing, it is highly scrutinized. Thus, billing professionals must ensure they report the modifier in accurate scenarios only. These may include:
Spinal Adjustment for Lower Back
Imagine an established 66-year-old female patient who presents to a chiropractor with acute low back pain. Following examination, the chiropractor documents a lumbar vertebral subluxation supported by relevant neuromusculoskeletal findings and identifies the spinal region treated. The chiropractor performs an appropriate chiropractic manipulative treatment (CMT) on two spinal regions to provide active/corrective treatment for the subluxation.
Because the service is intended to treat the documented acute subluxation and has a reasonable expectation of improving the patient’s function, the AT modifier is appended to the CMT code 98940 when billing Medicare. However, this modifier would not be appropriate if the service were maintenance therapy.
Treatment Plan with Measurable Functional Goals
Consider the case of a new 68-year-old male, evaluated by a chiropractor. The chiropractor develops a treatment plan with measurable goals to:
- Reduce pain
- Improve lumbar range of motion
- Restore the patient’s ability to perform daily activities
The plan is expected to show improvement in four weeks. However, it requires continued CMT of three spinal regions to achieve these functional outcomes via active corrective care.
The AT modifier is appended to CPT code 98941 because the treatment represents active corrective care rather than maintenance therapy.
Follow-Up Active Corrective Care
Consider an established 72-year-old male who appears for a follow-up chiropractic care at the chiropractor’s clinic. The chiropractor reviews the progress notes, which indicate improvements in:
- Mobility
- Spinal function
- Pain
The findings from the examination indicate a resolving spinal subluxation. Ongoing chiropractic manipulative treatment is continued as active corrective care to complete subluxation correction in two spinal regions and support continued functional recovery.
AT modifier is appended to CPT code 98940 because the patient continues to receive active corrective treatment for a documented spinal subluxation in two regions.
Inappropriate Use of AT Modifier
Now that we have discussed appropriate scenarios, it is essential to discuss when the modifier cannot be used:
- Modifier AT should be reported only when CMT is active/corrective care that is medically necessary to treat a documented spinal subluxation.
- AT should not be used once the patient has reached maximum therapeutic benefit. After that, visits are performed to prevent symptom recurrence.
- Medicare does not cover preventive or maintenance chiropractic services.
If the billing staff continues appending the AT modifier for maintenance care, the claims may be denied, subjected to post-payment review, recoupment, or audit.
AT Modifier – Billing Guidelines
Appropriate billing for modifier AT is only possible if the billing staff understands the guidelines and latest requirements properly. Therefore, the following are the most crucial billing requirements professionals should remember:
Document a Covered Spinal Subluxation
Document the spinal subluxation according to Medicare requirements and support medical necessity using the PART examination findings with at least two of four findings, including:
- Pain/tenderness (P)
- Asymmetry (A)
- Range of motion abnormality (R)
- Tissue/tone changes (T)
Note that at least one finding must be objective (A or R) to support active treatment billed with the AT modifier.
Maintain Visit-Specific Documentation
The patient’s visit should be properly recorded for reimbursement purposes. Therefore, the service provider should record:
- Functional changes
- Justification for continued active care
- Patient’s response to treatment
- Objective or subjective progress
Establish an Active Treatment Plan
The modifier AT is applicable for active treatment plans, which can only be established if the chiropractor formulates a treatment plan with:
- Measurable goals
- Document expected functional improvement
- Functional outcomes
- Appropriate frequency/duration of care
Avoid Pairing With Denial Modifiers
Appending the AT modifier with denial modifiers can be a serious billing error, leading to claim delay, denial, or a claim audit. Modifier AT generally should not be reported with denial modifiers such as:
These modifiers represent different Medicare billing circumstances.
Active/ Corrective Treatment
Before submitting claims involving CPT 98940–98942, ensure the documentation supports active/corrective treatment if using modifier AT. If the services are maintenance therapy, do not append modifier AT.
When appropriate and permitted, obtain a valid Advance Beneficiary Notice (ABN) before providing non-covered maintenance services. Proper documentation and modifier use can help reduce claim denials and ensure claims are ready for audit.
Summary
The AT modifier is a simple, two-letter indicator, but it can lead to outsized consequences. When used correctly, the modifier helps establish eligibility for Medicare reimbursement.
However, if reported incorrectly, it results in direct denials, recoupments, and audits. Therefore, billing the modifier requires more than just following the rules. Billing professionals must also know the:
- Documentation requirements
- Claim review processes
- Payer-specific nuances
If your practice struggles with compliant chiropractic claim submissions, MediBillMD’s medical billing services ease chiropractic billing for you.
