Chiropractic Medicare billing
Chiropractic Medicare Billing: The Rules That Get Claims Denied
Original Medicare covers a limited chiropractic benefit. Here are the rules behind the denials, and how we catch them before your claims go out.
What’s covered
Medicare covers exactly one chiropractic service, and it’s narrower than most practices think.
Under the chiropractic benefit, Medicare Part B covers manual manipulation of the spine to correct a subluxation, and nothing else. It does not pay for the exam, the X-rays, the therapies, the supplies, or anything extraspinal. That single covered service is billed with three CPT codes, and every one of them lives or dies on documentation that proves the care is active, not maintenance.
Correct codes, modifiers, dates and diagnosis order help prevent avoidable denials. Payment also depends on coverage, medical necessity and the supporting documentation. Use the denial reason to identify what needs review. Below is the rulebook, the way an experienced chiropractic biller reads it, and how our billing service catches each failure before the claim ever leaves your practice.
98940 / 98941 / 98942
- 98940: CMT, spinal, 1 to 2 regions
- 98941: CMT, spinal, 3 to 4 regions
- 98942: CMT, spinal, 5 regions
Payable only with the AT modifier and documentation that substantiates a subluxation.
98943 & everything else
- 98943: extraspinal CMT (head, extremities, ribs, abdomen)
- Exams & E/M, X-rays, and the X-ray reading
- Therapies (97110, 97140), supplies, supports
Excluded from the Original Medicare chiropractic benefit. A voluntary ABN or similar notice can explain the cost to the patient (see below).
The AT modifier
No AT modifier? Medicare reads your CMT as maintenance, and denies it.
The AT modifier (Active/Corrective Treatment) is the single most important element on a chiropractic Medicare claim. Append it to 98940, 98941, or 98942 to tell Medicare the manipulation is meant to improve the patient’s condition. Leave it off and the MAC treats the visit as maintenance care (which is never covered) and denies it as not medically necessary.
That denial comes back as CO-50: “non-covered services because this is not deemed a medical necessity by the payer.” It is one of the most common chiropractic Medicare denials, and one of the most avoidable. The flip side matters just as much: appending AT to a visit that is genuinely maintenance is a compliance violation that invites recoupment and post-payment records audits. The AT modifier is not a checkbox to make claims pay. It is a clinical attestation, and it has to be true.
Where the line sits (active vs. maintenance) is a clinical decision the provider documents. Our job is to make sure the claim matches the documentation: AT on the visits the note supports as active care, and an honest patient bill on the rest. We never quietly add AT to make a denial disappear.
Denial codes
Chiropractic Medicare denial codes (CO-50, CO-16, CO-11): what each one is really telling you.
A denial code is a diagnosis. Each one points at a specific failure upstream, and once you can read them, the same handful of fixes clears the vast majority of chiropractic Medicare rejections.
Not medically necessary
Check the AT modifier, active-care documentation and coverage policy. CO-50 identifies a medical-necessity denial; the accompanying remark codes help identify what needs correction.
Claim lacks information
Required claim information is missing or incorrect. Read the accompanying remark code and check the indicated field, including the initial treatment date in Item 14. CO-16 is not a request for chart attachments.
Dx inconsistent with procedure
The primary diagnosis or its pointer doesn’t support the spinal region billed: the subluxation code and the CMT region disagree.
None of these are mysteries. They’re the symptoms of four upstream rules, covered next: the initial treatment date, PART documentation, diagnosis order, and the AT modifier.
Initial Tx date
The date active care began belongs in Item 14, every time.
Medicare requires the date of the initial treatment, or the date of the exacerbation of an existing condition, on every active-care CMT claim. It goes in Item 14 of the CMS-1500 form (or its electronic equivalent in any EHR). This date anchors the episode of care and tells Medicare the manipulation is part of an active treatment plan with a beginning, not open-ended maintenance.
Leave it off and the claim is missing required information, and the whole thing bounces back as CO-16. It’s a clerical miss with a clinical-sounding denial, and it’s one of the easiest to prevent and the easiest to overlook in a busy practice.
The PART exam
PART is how you prove the subluxation is real.
A subluxation has to be demonstrated, not just stated. Medicare accepts either an X-ray or a physical exam to substantiate it, and the physical-exam standard is the PART framework. Document at least two of the four PART criteria, and at least one of the two must be Asymmetry or Range-of-motion. The note then needs the exact level of the subluxation and a plan of care with measurable goals.
2 of 4, and one must be A or R
Pain and tissue-tone findings alone don’t carry the claim; Medicare wants objective evidence of the misalignment or the lost motion. The note must also state the precise subluxation level and tie it to a plan of care with goals you can measure visit-to-visit.
Where an X-ray is used instead, its date has to support the episode. Medicare generally accepts an X-ray taken within 12 months before or 3 months after treatment begins, with an older-film exception for documented permanent chronic subluxation.
Diagnosis order
The subluxation is the primary diagnosis, and it has to match the region.
On a Medicare CMT claim the primary diagnosis must be the subluxation, coded in the M99.0x family (segmental and somatic dysfunction), and it must correspond to the spinal region you actually manipulated. The neuromusculoskeletal complaint that justifies the care (the M54.x back and neck pain codes, for example) is a supporting secondary diagnosis. It cannot stand alone as primary for CMT.
Then the diagnosis pointers have to line up: the CMT line points to the subluxation level that matches its region. When the primary diagnosis, the region, and the pointer disagree, check the denial and remark codes. CO-11 identifies a diagnosis inconsistent with the procedure. It’s a quiet error that a generalist biller, working from a template, misses constantly.
ABN & maintenance
When care becomes maintenance, the ABN is what protects the practice.
Active care eventually reaches a plateau. When no further clinical improvement is reasonably expected and care aims to maintain a stable condition or prevent deterioration, the care becomes maintenance, and Medicare won’t pay. Active treatment of an acute subluxation may also aim to arrest its progression. That isn’t a billing problem; it’s a coverage line. The mistake is pretending it isn’t.
For Original Medicare, issue a valid Advance Beneficiary Notice of Noncoverage (ABN, form CMS-R-131) before maintenance CMT when you expect a medical-necessity denial and intend to transfer financial liability to the patient. If a required ABN is missing or invalid, the practice may be liable. An ABN is voluntary for services excluded from the chiropractic benefit, such as extraspinal 98943, exams, X-rays and therapies furnished by a chiropractor. A voluntary ABN or similar notice helps explain the patient’s costs. Medicare Advantage uses its own coverage and notice procedures; do not use the Original Medicare ABN for those services. Our ABN guide covers the form, modifiers and timing.
The honest path: identify the coverage category before treatment. Active spinal CMT needs the AT modifier and supporting documentation. Maintenance CMT needs a valid advance ABN to transfer liability for an expected medical-necessity denial. Excluded services can use a voluntary notice. Patient billing must also follow applicable Medicaid and other liability protections. That’s exactly the line our coordinators help you hold.
Claim scrubbing
Every rule above is a scrub check, run before the claim is ever submitted.
A “clean claim” that wasn’t rejected can still be denied. We scrub each chiropractic Medicare claim against the exact failure points on this page: the AT modifier, the initial treatment date, PART and X-ray documentation, and the diagnosis order. That way it pays the first time instead of bouncing back weeks later.
And it’s consultative, not just defensive. The same revenue-optimization review that prevents denials catches the money generalists miss: undercharged E/M visits, codes left off the claim, CPT lines priced below the fee schedule. Many of our clients run multi-specialty centers, so the same coordinator also bills the therapy (97110, 97140), massage, acupuncture, and nurse-practitioner visits under your roof, with the Medicare-specific rules applied correctly across all of them. It’s all one flat fee, laid out on our pricing page.
Proof
The expertise shows up in the collections.
“In practice over 30 years, I have never found a more professional, knowledgeable company. I have a dedicated person accessible at all times, and they’re compatible with my EHR so I have no extra steps.”
“ACB has been instrumental in cleaning up our accounts receivable, helping us transition between software, and staying on top of all our billing. Knowledgeable, and most importantly, effective.”
“I used to spend a lot of time calling insurance companies when claims weren’t paid. Now they’re part of my team, so I can focus on patient care. Highly recommend.”
FAQ
Chiropractic Medicare billing, answered.
The AT (Active/Corrective Treatment) modifier tells Medicare the spinal manipulation is intended to improve the patient’s condition, not just maintain it. Without AT on 98940, 98941, or 98942, Medicare treats the visit as maintenance care (which it never covers) and denies it as not medically necessary (CO-50). It should only be applied when the documentation genuinely supports active care; using it on a maintenance visit is a compliance violation.
No. The Medicare chiropractic benefit covers only manual manipulation of the spine to correct a subluxation: codes 98940, 98941, and 98942. Extraspinal manipulation (98943, for the head, extremities, ribs, and abdomen) is statutorily excluded. An ABN is voluntary for this excluded service. A voluntary ABN or similar notice can explain noncoverage and the expected cost; follow any other applicable patient-liability rules.
CO-16 means required claim information is missing or incorrect, separate from the AT issue. Read the accompanying remark code and check the indicated field, such as the initial treatment date in Item 14 of the CMS-1500 (the date treatment began or the condition was exacerbated). Chart attachments and PART findings are a separate documentation check; CO-16 does not identify missing chart records.
The subluxation must be the primary diagnosis, coded in the M99.0x family (segmental and somatic dysfunction) and matched to the spinal region treated. The pain or neuromusculoskeletal complaint (for example an M54.x code) is a supporting secondary diagnosis and cannot stand alone as primary for CMT. If the primary diagnosis, the region, and the diagnosis pointers don’t agree, Medicare returns CO-11.
In Original Medicare, a valid ABN must be given before a usually covered service, such as spinal CMT, when a medical-necessity denial is expected and you intend to transfer liability to the patient. Maintenance CMT falls in that category. For excluded services such as 98943, exams, X-rays or therapy furnished by a chiropractor, the ABN is voluntary. A missing or invalid required ABN may leave the practice liable. Medicare Advantage has separate coverage and notice procedures. We help you keep active care, maintenance care and excluded services on the right billing and notice paths.
Pricing
All of this, for 7% of net collections.
Medicare scrubbing, denials and appeals, the AT-and-documentation review on every CMT claim, your dedicated coordinator, and the consultative revenue work. It’s all included in one performance-based fee: 7% of net collections, or a $1,500/month minimum, whichever is greater. All-inclusive, month-to-month, no contract. See the full breakdown and run the numbers on our pricing page.
Official sources
Where these rules come from
Last reviewed October 8, 2026. The coverage, modifiers, documentation and denial-code instructions on this page were checked against the primary sources below. Apply the MAC policy for the patient’s jurisdiction and date of service.
- CMS · ABN Tutorial (April 2026): mandatory & voluntary notices
- CMS · Billing & Coding: Chiropractic Services (A56273)
- CMS · Local Coverage Determination: Chiropractic Services (L37254)
- Medicare.gov · Chiropractic services coverage
- CMS · Advance Beneficiary Notice of Noncoverage (ABN, Form CMS-R-131)
- CMS · Benefit Policy Manual, Chapter 15: chiropractic coverage and documentation
- CMS · Claims Processing Manual, Chapter 12: chiropractic claim fields
- X12 · Claim Adjustment Reason Codes
Billing rules also vary by state. See our state-by-state chiropractic billing guides. Each covers the local auto-injury, Workers’ Comp and Medicaid rules, cited to the governing statute.
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