The modifier AT is assigned to the CPT codes 98940–98944 for spinal manipulation when active therapy is performed in chiropractic care. The insurance company will reject claims for CPT codes 98940–98942 without a modifier AT because they are not medically essential.

Before the addition of the modifier AT, i.e., Active Treatment, the distinction between active treatment and maintenance treatment was unclear. Medicare only covers active or corrective treatment, regardless of how long the subluxation has been. Medicare does not pay for any maintenance therapy.

Claims may be denied if you bill using incorrect chiropractic CPT codes, and compensation may be delayed. These factors can reduce your earnings and your capacity to remain in business. The present post puts forward guidelines for receiving Medicare reimbursements with the modifier AT.

Let’s grasp the AT modifier for Medicare to have a greater possibility of being reimbursed.

What is Modifier AT?

The Centers for Medicare & Medicaid Services (CMS) describes the modifier AT to assist providers in submitting claims for chiropractic services rendered to Medicare enrollees.

The AT modifier for Medicare was created to distinguish between active and maintenance treatments. The claims for CPT codes 98940–98942 must include the modifier AT to be covered by Medicare.

Chiropractic physicians should only apply the AT modifier when billing Medicare for active/corrective treatment. Maintenance treatment does not operate when the AT modifier is used.

AT Modifier Medicare Usage

The following categories are used to determine the coverage of chiropractic treatment:

Acute Subluxation: When a patient is treated for a new injury, the condition is referred to as acute subluxation. Chiropractic manipulation will improve the patient’s condition or prevent it from worsening.

Chronic Subluxation: A patient’s condition is deemed chronic when it is unlikely to improve or disappear with more treatment (as it would with acute disease), but it is likely to improve in some respects with prolonged therapy. This differs from a critical ailment, where additional treatment is anticipated to make the patient much better or eliminate the condition. When the clinical status of a disease remains unchanged, continued treatment is referred to as maintenance therapy, and the patient’s insurance company does not cover it.

Medicare will pay for the treatments if they are properly documented. Acute subluxations, such as strains and sprains, can take up to three months to cure, but in some cases, only a few treatments are required. Initially, treatment may need to be administered more frequently, but this frequency should decrease over time or when progress is made. A chronic spinal joint problem indicates that the issue has persisted for an extended period and that the damaged joints have likely improved and developed fibrotic tissue. This is because chronic diseases tend to stay for longer durations.

Maintenance therapy is the provision of services to prevent disease, enhance health, extend life, and prevent a chronic condition from worsening. Medicare considers chiropractic care to be maintenance therapy when it cannot be expected that the patient will improve with additional care and when the care focuses on assisting the patient rather than correcting the problem. There is no need to apply the AT modifier of Medicare to maintenance therapy because it is already covered.

Guidelines for AT Modifier for Medicare Reimbursements

You must adhere to the following billing guidelines to receive Medicare reimbursements for AT modifier:

  • The claim should include a primary diagnosis of subluxation and a secondary diagnosis describing the neuromusculoskeletal condition of the patient. The patient’s medical record should contain evidence of the services being invoiced.
  • If an insurance claim for a chiropractor is denied, the policyholder must send the chiropractor an Advance Beneficiary Notice (ABN).
  • If the progress is not detected, the treatment will enter maintenance mode, and Medicare will no longer cover it.
  • When submitting claims for active or corrective treatment to treat acute or chronic subluxation, chiropractors must include an AT modifier. However, it does not always indicate that the service is appropriate and required. If a medical examination determines that the medical record does not support active or corrective therapy, MACs (Medicare Administrative Contractors) can deny claims.

You should know how chiropractic services are billed in your region and whether Local Coverage Determinations (LCDs) exist. Medicare may not cover all active or corrective chiropractic services due to these regulations.

See Also: Strategies to Minimize Revenue Loss in Medical Billing


When chiropractic care includes active therapy, the CPT codes 98940-98944 for spinal manipulation use the modifier AT. Without the appropriate AT modifier for Medicare, the insurance company will deny payment for services rendered under these CPT codes. Using the wrong chiropractic CPT codes when billing can deny claims and delay payment. Precision Hub is the solution if you have issues with denied insurance claims, personnel spending too much time attempting to have claims paid, and patients questioning why their claims have not been paid.

Precision Hub maintains abreast of the most recent billing and coding trends and changes by maintaining contact with insurance companies and rule-setting organizations. In addition to saving you thousands of dollars, our tried-and-true procedures will expedite the processing of your claims. We are familiar with Medicare billing procedures for chiropractic services and use the correct procedure codes and modifiers. Don’t hesitate to contact us at (888) 454-4325 if you have any questions about our chiropractic billing services. You can also book your free demo by filling out our contact form.

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