Key Takeaways
- Medicare covers exactly one chiropractic service: manual spinal manipulation to correct a subluxation. Every other service a chiropractor commonly provides — x-rays, E/M visits, massage, e-stim, ultrasound, extraspinal manipulation — is statutorily excluded.
- The AT modifier is required on every Medicare claim for spinal manipulation. Without it, the MAC denies the claim automatically, without review.
- Maintenance care is not a covered Medicare benefit. When a patient reaches maximum therapeutic benefit, the AT modifier must be dropped and an Advance Beneficiary Notice obtained before continuing treatment.
- CMS released an updated ABN form in 2026 with a mandatory compliance deadline of May 12, 2026 — practices still using the prior form face claim disputes and potential liability exposure.
- Chiropractic has historically carried one of the higher improper payment rates in Medicare, driven primarily by documentation that fails to distinguish active treatment from maintenance care.
- Managing Medicare compliance in a chiropractic practice requires ongoing attention to modifier use, documentation standards, and ABN workflows.
Medicare’s chiropractic benefit is one of the most narrowly defined in all of Part B. Practices that don’t understand exactly where the coverage boundary sits — and what happens on either side of it — tend to find out through denials, audits, and billing disputes that could have been prevented.
This post covers what Medicare actually covers for chiropractic services, what it explicitly does not, and where billing errors concentrate in practices that serve a significant Medicare patient population. For a closer look at the CPT coding mechanics behind chiropractic claims — region counts, ICD-10 alignment, and modifier application — our post on chiropractic billing codes and denial patterns covers that ground in detail.
What Medicare Actually Covers: One Service, Narrowly Defined
Medicare Part B covers manual spinal manipulation to correct a subluxation of the spine. That is the entirety of the chiropractic benefit under Original Medicare — one service, billed using CPT codes 98940, 98941, or 98942 depending on the number of spinal regions treated and documented.
For that service to be covered, four conditions must be met:
- The treatment must be directed at correcting a documented subluxation
- The subluxation must be identified by precise spinal level in the ICD-10 diagnosis code, listed as the primary diagnosis on the claim
- The neuromusculoskeletal condition necessitating treatment must be listed as the secondary diagnosis
- The treatment must represent active, corrective care with a reasonable expectation of measurable improvement
When all four conditions are met and the AT modifier is appended to the claim, Medicare pays 80% of the approved amount after the $283 Part B deductible (2026 rate). When any one of them is missing or unsupported by documentation, the claim is denied or subject to recoupment after audit.
What Medicare Does Not Cover: A Long and Specific List
The exclusions in Medicare’s chiropractic benefit are statutory — written into federal law, not set by individual payer policy. Every service a chiropractor orders or performs other than spinal manipulation for subluxation is excluded from Medicare coverage. That list includes:
- Initial examinations and E/M visits
- X-rays ordered, taken, or interpreted by the chiropractor
- Extraspinal manipulation (CPT 98943) — treatment of the extremities, rib cage, or TMJ
- Massage therapy
- Electrical stimulation
- Therapeutic ultrasound
- Traction
- Therapeutic exercises
- Nutritional counseling and supplements
- Laboratory tests and other diagnostic studies
Two points matter for practices that provide these services alongside spinal manipulation. First, the exclusion applies specifically when the service is furnished by the chiropractor — if a physician orders imaging and it is performed at a radiology facility, Medicare coverage rules for that service apply separately. Second, when a patient requests that a non-covered service be submitted to Medicare anyway — typically to generate a denial for secondary insurance purposes — the chiropractor may submit the claim using the appropriate modifier. That is different from billing non-covered services as if they were covered, which is a compliance violation.
The AT Modifier: Required on Every Claim
The AT modifier on CPT codes 98940, 98941, and 98942 is Medicare’s mechanism for distinguishing active treatment from maintenance care. Claims submitted without it are automatically denied by the MAC without review — no adjudication of whether the service was otherwise appropriate, no opportunity to appeal the clinical merits. No modifier, no payment.
What practices underestimate is that the modifier’s presence does not itself establish medical necessity. Medicare’s standard is that the patient must have a significant neuromusculoskeletal condition requiring treatment, the manipulation must have a direct therapeutic relationship to that condition, and there must be a reasonable expectation of recovery or improvement of function. The -AT modifier is the claim-level signal that those conditions are met — but the clinical record has to actually support it.
This is where OIG scrutiny has historically concentrated in chiropractic. Audits have consistently found that a meaningful share of Medicare chiropractic payments have been unallowable, with maintenance care billed as active treatment as the primary driver. The documentation discipline required to maintain that distinction — visit by visit, across a recurring patient panel — is genuinely demanding, and practices that treat it as a formality rather than a substantive clinical and billing responsibility are the ones most exposed.
Maintenance Care: The Line That Determines Coverage
Maintenance care is treatment that seeks to maintain a patient’s current condition or prevent deterioration, rather than produce measurable functional improvement. Medicare does not cover it. Once a patient reaches maximum therapeutic benefit — the point at which no further improvement is expected — the AT modifier must be dropped from subsequent claims.
That transition has two practical requirements. The clinical record must document that maximum therapeutic benefit has been reached. And before continuing treatment as maintenance care, the practice must obtain a signed Advance Beneficiary Notice of Noncoverage from the patient, informing them that Medicare will not cover the service and that they will be personally responsible for the cost. Without a properly executed ABN, the practice cannot transfer financial liability to the patient if Medicare denies — the cost stays with the practice.
Subsequent maintenance care claims are billed with modifier GA to indicate an ABN is on file. Getting the documentation right on both sides of this transition — establishing active treatment clearly while it’s occurring, and documenting the determination of maximum benefit when it’s reached — is the practice’s primary protection against both denials and audit exposure.
The Updated ABN Form: A 2026 Compliance Item Worth Verifying
CMS released an updated version of the ABN form (Form CMS-R-131) in early 2026, with a mandatory compliance deadline of May 12, 2026. Practices using the prior version after that date face claim disputes and potential difficulty transferring financial liability to patients when Medicare denies maintenance care claims.
The updated form is operationally simpler — providers no longer need to repeat certain item descriptions in multiple sections — but the situations that require an ABN and the form’s overall purpose are unchanged. The meaningful operational task was updating stored templates in practice management systems and replacing printed copies used by front desk and billing staff.
For any chiropractic practice that hasn’t confirmed its ABN workflows reflect the current form, that is worth checking now.
Where Billing Errors Concentrate in Medicare Chiropractic Claims
In working with chiropractic practices, the Medicare billing problems we see most consistently follow a recognizable pattern:
- AT modifier applied without documentation support. The modifier is on the claim; the clinical record doesn’t establish measurable improvement or a reasonable expectation of recovery. The claim pays initially but is vulnerable to recoupment in a post-payment audit.
- Maintenance care billed as active treatment. The most common source of Medicare chiropractic improper payments. Often stems from not formally reassessing patient status at regular intervals and documenting the findings.
- Non-covered services billed without appropriate modifiers. E-stim, ultrasound, or other ancillary services submitted as if covered rather than with the modifier that correctly identifies their non-covered status.
- ABN not obtained before maintenance care begins. Medicare denies the claim, there is no ABN on file, and the practice absorbs the cost with no recourse.
- Diagnosis code specificity gaps. The subluxation level must be identified precisely in the ICD-10 code and listed as the primary diagnosis — vague or unspecified codes leave claims without the specificity Medicare requires.
Pre-submission review that checks modifier presence, diagnosis code specificity, and the consistency between the AT modifier and supporting documentation catches most of these before they reach the payer. PGM’s AI-powered claim scrubber validates how CPT codes, modifiers, and diagnosis codes interact with each other and with Medicare’s coverage requirements — not just whether each element is individually present.
Medicare Chiropractic Compliance Is a System
The coverage rules, modifier requirements, ABN obligations, and documentation standards in Medicare chiropractic billing are interconnected. A claim can carry the right CPT code, the right diagnosis codes, and the AT modifier — and still be vulnerable to recoupment if the clinical documentation doesn’t establish active treatment clearly enough to withstand review. Accurate coding is necessary but not sufficient.
Managing that exposure consistently across a practice requires billing expertise specific to chiropractic. The program pays close attention to this specialty — the history of OIG scrutiny reflects that — and practices with Medicare patients benefit from a billing operation that understands not just how to submit claims, but how Medicare evaluates them.
PGM Billing works with chiropractic practices to manage Medicare compliance, reduce denials, and strengthen revenue cycle performance across the full range of chiropractic services. If your practice serves Medicare patients and billing is creating more work than it should, let’s talk about what a specialist team handles differently.
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Frequently Asked Questions About Medicare Chiropractic Billing
Does Medicare cover chiropractic E/M visits or initial examinations?
No. E/M visits performed by a chiropractor are statutorily excluded from Medicare coverage. The initial examination is not covered, and the patient is responsible for that cost out of pocket. This is a common source of patient confusion — and billing disputes — when practices don’t communicate it clearly before the visit.
What happens if the AT modifier is missing from a chiropractic claim?
The MAC denies the claim automatically without reviewing whether the service was otherwise appropriate. Resubmission with the modifier corrected is generally possible, but it adds rework and delays reimbursement. Pre-submission review eliminates this category of error before it reaches the payer.
How does a practice handle the transition from active treatment to maintenance care?
Once a patient reaches maximum therapeutic benefit, the AT modifier should no longer be used. Before continuing treatment as maintenance care, the practice must obtain a signed ABN from the patient explaining that Medicare will not cover the service and that the patient will be financially responsible. Subsequent maintenance care claims are billed with modifier GA indicating the ABN is on file. The clinical record should document the basis for the determination that maximum benefit has been reached.
Does Medicare impose an annual visit limit for chiropractic care?
No hard annual visit cap exists under Original Medicare. However, every visit must be supported by documentation demonstrating medical necessity and a reasonable expectation of improvement. High-frequency treatment patterns — particularly sustained treatment beyond 30 days without documented reassessment — can draw MAC review. The absence of a visit cap means each visit is individually subject to the medical necessity standard.
Can a general billing team manage Medicare chiropractic compliance effectively?
It can be managed, but the compliance demands are specific enough that general billing experience doesn’t fully substitute for chiropractic expertise. The active treatment versus maintenance care distinction, ABN workflow requirements, modifier sequencing, and diagnosis code specificity requirements all interact in ways that require ongoing familiarity with CMS guidance and MAC-specific policies. Practices with Medicare patients tend to see better outcomes — fewer denials, less audit exposure — with billing support that specializes in chiropractic.