Chiropractic Billing Guide 2026
CMT Codes, AT Modifier, and Medicare Rules
Chiropractic billing operates under a unique set of rules that differ significantly from standard medical billing. The combination of Medicare's strict subluxation documentation requirements, the mandatory AT modifier, and the detailed CMT code selection criteria makes chiropractic one of the highest-denial specialties in outpatient care. This guide covers every critical billing rule you need to maximize collections and minimize audit risk in 2026.
1. CMT Codes: Selecting the Right Level
Chiropractic Manipulative Treatment (CMT) codes are billed based on the number of spinal regions treated, not the complexity of the visit or the time spent. There are five spinal regions: cervical, thoracic, lumbar, sacral, and pelvic. Selecting the wrong region count is the most common coding error in chiropractic billing.
| CPT Code | Regions Treated | 2026 Medicare Rate (approx.) | Key Rule |
|---|---|---|---|
| 98940 | 1–2 spinal regions | $37–$42 | Most common for focused cervical or lumbar visits |
| 98941 | 3–4 spinal regions | $54–$61 | Document each region manipulated in SOAP notes |
| 98942 | 5 spinal regions | $71–$79 | All 5 regions must be documented; rarely appropriate |
| 98943 | Extraspinal regions | $28–$34 | Non-covered by Medicare; bill to patient or secondary |
Critical rule: The number of spinal regions must match exactly what is documented in the SOAP note. Billing 98941 when only the lumbar and sacral regions are documented is upcoding, a common audit trigger. Each region treated must have a corresponding subluxation finding documented.
2. The AT Modifier: Medicare's Gateway to Payment
For Medicare patients, chiropractic CMT codes (98940–98942) must be appended with modifier AT (Acute Treatment) to receive payment. Without AT, Medicare will automatically deny the claim as maintenance care, which is explicitly non-covered.
AT vs. Non-AT Billing: The Distinction
- With AT modifier: Patient must have an acute or subacute condition that's actively improving (or has expectation of improvement). Medicare covers this.
- Without AT modifier: Maintenance care, keeping a stable condition from deteriorating. Medicare does NOT cover this. Bill patient directly (with proper ABN on file).
The key documentation question for every Medicare visit: Is this patient making measurable functional improvement? If yes, use AT. If the patient has plateaued and treatment is maintaining function, that's maintenance care, document accordingly, issue an ABN, and bill the patient directly.
Advanced Beneficiary Notice (ABN) Requirements
When a Medicare patient transitions from active/acute to maintenance care, you must issue a signed ABN (Form CMS-R-131) before the maintenance visit. The ABN informs the patient that Medicare won't cover the service and they will be responsible for payment. Failure to obtain a signed ABN before a non-covered service means you can't bill the patient; you absorb the cost.
3. Subluxation Documentation: The Foundation of Every Claim
Medicare requires documentation of subluxation as the basis for chiropractic coverage. Subluxation must be documented using one of two methods:
Method 1: X-ray Evidence
A documented X-ray finding showing subluxation. The X-ray must be taken by or for the treating chiropractor and must correlate with the region being treated.
Method 2: Physical Examination Evidence (P-A-R-T)
In the absence of X-ray evidence, subluxation must be demonstrated through physical examination using the P-A-R-T criteria:
- P: Pain/tenderness: Documented at the site of subluxation
- A: Asymmetry/misalignment: Documented on static or motion palpation
- R: Range of motion: Abnormality documented with objective measurements
- T: Tissue/tone changes: Documented muscle spasm, hypertonicity, or atrophy
At least two of the four P-A-R-T components must be documented for each subluxation. Many practices document all four to avoid any vulnerability during audits.
4. Manual Therapy and Other Billable Codes
CMT codes cover spinal manipulation only. Chiropractors often provide additional services that are separately billable, when documented as distinct, medically necessary services that go beyond the manipulation itself.
| CPT Code | Service | Billing Rule |
|---|---|---|
| 97140 | Manual therapy (joint mobilization, soft tissue) | Must be distinct from CMT; document time and technique; modifier 59 may be needed |
| 97110 | Therapeutic exercise | Separately billable; document sets/reps and direct supervision |
| 97012 | Mechanical traction | Billable when provided; document time and region |
| 97530 | Therapeutic activities | Functional movement training; must be therapist-directed |
| 99213–99214 | E/M visit (if applicable) | Only if chiropractor is licensed to bill E/M in your state; requires separate E/M documentation |
5. Medicare's 12-Visit Rule and Plan of Care Requirements
While Medicare doesn't have a hard visit limit for chiropractic, it requires that each visit have documented medical necessity. In practice, Medicare closely scrutinizes claims beyond 12 visits per episode of care. Best practices:
- Establish and document a formal Plan of Care (POC) at the initial visit with specific, measurable treatment goals and expected visit frequency/duration
- Re-evaluate and update the POC every 12 visits or when goals are met
- Document objective functional improvement at re-evaluation (e.g., pain score reduction, increased ROM, improved ADL function)
- When the patient plateaus, transition to maintenance documentation and issue ABN
6. Common Denial Reasons and How to Prevent Them
| Denial Reason | Root Cause | Prevention |
|---|---|---|
| Missing AT modifier | Claim submitted without AT for Medicare | Claim scrubber rule: flag any 98940–98942 for Medicare without AT |
| Insufficient subluxation documentation | SOAP note lacks P-A-R-T findings for each region billed | EHR template with mandatory P-A-R-T fields per region |
| Upcoding CMT region count | 98941 billed but only 2 regions documented | Auto-populate CMT code from documented regions in EHR |
| Maintenance care denial | AT applied to plateau patient without ABN | Functional improvement checklist at every visit; ABN workflow |
| 97140 bundled with CMT | Manual therapy not documented as distinct service | Separate documentation section for manual therapy; modifier 59 |
Chiropractic Audit Exposure: Medical Necessity and Repeat Reviews
Chiropractic is one of the most reviewed specialties in Medicare. The reasons are structural: coverage is limited to manual manipulation of the spine to correct a subluxation, and the claim has to show active treatment, not maintenance care. Reviewers look at the initial evaluation, the documented subluxation, the functional goals, and whether the notes show improvement over time or simply repeat themselves.
The OIG has reviewed chiropractic claims for medical necessity, and contractors pay the most attention to long series of visits with cloned notes. Medicare lets reviewers go back three years, and a sample of denied visits can be extrapolated to the whole population. Reviewing your own notes every quarter, looking for identical wording across patients, is how you find the pattern before they do.
Building Notes That Show Progress, Not Repetition
The strongest chiropractic notes show a patient getting better, or explain why not. Start with a baseline: pain scores, range of motion, and functional limits. At each visit, record what changed and compare it to the baseline. Set treatment goals that are measurable and review them at defined intervals.
When a patient plateaus, say so, and describe what you'll change. That kind of honesty reads as clinical judgment and supports the claim. Notes that repeat the same words visit after visit suggest maintenance care, which is exactly what Medicare doesn't cover.
Chiropractic Note Checklist
- AT modifier on Medicare manipulation claims.
- Subluxation documented by an accepted method.
- Measurable goals and progress at each review.
- No copied text between patients or visits.
Frequently Asked Questions About Chiropractic
Why does Medicare require the AT modifier on CMT codes?
AT tells Medicare the manipulation was active, corrective treatment rather than maintenance care. Without it on 98940 to 98942, the claim is treated as maintenance care and denied, which the article notes is explicitly not covered.
How is the CMT code level chosen?
By the number of spinal regions treated, not by time or visit complexity. There are five regions, and the code moves from 98940 up to 98942 as more of them are treated and documented.
Can you bill other services on the same day as a CMT?
Yes, when they're separately identifiable and medically necessary. The article lists manual therapy and other codes that can be billed alongside, but the documentation has to show the service went beyond the manipulation itself.