Chiropractic practices lose revenue every day to a problem that is entirely preventable. A claim goes out for a legitimate spinal adjustment, the documentation is thorough, the diagnosis is accurate, and yet the claim comes back denied. The reason? A missing two-character modifier. For spinal treatment, in most cases, this two-digit indicator is modifier AT.
In this guide, we will explain what the AT modifier is, walk you through real-world scenarios where it applies, and share the billing guidelines you need to know to use it correctly. So, let’s start.
AT Modifier – Description
The AT modifier is defined as:
“Active/Acute treatment (chiropractic)”
AT is a Level II HCPCS modifier. As short as it appears, it has significant billing implications, so let’s break it down.
The modifier AT exists to solve one specific problem in chiropractic billing, i.e., Medicare only pays for chiropractic services if they are part of an active/corrective treatment plan. This is because Medicare does not cover maintenance therapy. Maintenance therapy simply means any ongoing care provided after a patient has reached maximum therapeutic benefit and is no longer expected to show functional improvement.
For processing the claim, Medicare must differentiate between the two: active treatment and ongoing care. The AT modifier solves this problem. When it is appended, it tells Medicare that the service being billed is active, corrective care aimed at treating acute or chronic subluxation of the spine, and that the treatment is medically necessary.
The important point to note here is that modifier AT is not for all services. Rather, it is limited to just three Chiropractic Manipulative Treatment (CMT) CPT codes. It is required on CPT codes 98940 (CMT, 1-2 spinal regions), 98941 (CMT, 3-4 spinal regions), and 98942 (CMT, 5 spinal regions).
Additionally, it is important to understand that AT applies to both acute and chronic subluxation scenarios.
A subluxation is classified as acute when it involves a new injury with a reasonable expectation of recovery. Conversely, it is classified as chronic when it involves a long-standing condition that is still expected to improve or stabilize with ongoing corrective care. So, if the condition no longer meets either of those criteria, and the patient is receiving care simply to maintain their current state, that is maintenance therapy, and the AT modifier must not be used.
Appropriate Use Cases for AT Modifier
Here are some real-world scenarios in which the AT modifier is applicable. Take a look.
Acute Low Back Pain After a Workplace Injury
Suppose a patient comes to a chiropractor. He had a workplace accident after which he felt sudden and sharp pain in his lower back. The chiropractor performs a physical examination and finds restriction in the lumbar range of motion. He also finds subluxation at L4-L5.
For treatment, the chiropractor develops a plan. He starts a course of spinal manipulation (CPT 98940) across multiple sessions over four weeks.
Now, since the patient never had this problem and it is a new condition, plus there is proof of subluxation, and a clear expectation of functional improvement, the billing team can append the AT modifier to 98940 CPT code to bill each session.
Chronic Cervical Subluxation
For this scenario, suppose a patient with a long-standing history of cervical subluxation presents for continued chiropractic care. Although the condition is chronic, the patient is still showing documented improvement in range of motion and reduction in reported pain levels with each re-evaluation. The chiropractor performs cervical and thoracic manipulation (CPT 98940) and records objective outcome measures at each visit, demonstrating measurable progress.
Because the treatment continues to produce functional improvement, this is still classified as active/corrective treatment under Medicare guidelines. Hence, the AT modifier applies.
Accurate Usage Guidelines for AT Modifier
To use modifier AT correctly in your claims, you need to consider the following essential guidelines:
Understand When AT Must Not Be Used
The single most important rule around the AT modifier is knowing when not to use it. AT must not be appended to any CMT claim where the service rendered is maintenance therapy.
Also, you must never use AT with denial modifiers like GA, GX, GY, or GZ on the same line.
Verify CPT Code Eligibility Before Appending AT
The AT modifier is only valid with CPT codes 98940, 98941, and 98942. CPT code 98943 (CMT, extraspinal regions including the head, upper and lower extremities, rib cage, and abdomen) is not covered by Medicare at all.
Appending AT to 98943 will not create coverage where none exists. All other services ordered or performed by a chiropractor, including X-rays, lab tests, and E/M visits, are excluded from Medicare coverage.
Maintain Documentation that Supports Active Treatment
For using modifier AT, the SOAP notes should include:
- Chief complaint for each spinal region treated.
- Objective findings, including motion palpation results, range of motion measurements, and subluxation characteristics.
- Treatment plan with stated goals, frequency, and duration.
- Progress notes demonstrating functional improvement or a clear expectation of improvement.
- The date of initial treatment or the date of exacerbation.
Wrapping Up
Let’s wrap up everything we have discussed.
- The AT modifier is used for chiropractic manipulative treatment claims submitted to Medicare.
- It must be appended to CPT codes 98940, 98941, and 98942 when the care provided is active, corrective treatment for acute or chronic subluxation.
- It must not be used for maintenance therapy.
- Proper diagnosis code pairing, timely re-evaluations, and accurate SOAP documentation are vital for claim reimbursement.
Chiropractic billing has one of the highest Medicare error rates across all provider specialties. That is why many chiropractic practices opt for professional medical billing and coding services. You too can connect with our experts at NeuraBill. We offer some of the best billing and revenue cycle management solutions in the industry with guaranteed results.
