Payers deny chiropractic claims for medical necessity when your notes don’t prove four things: a specific spinal problem, where it is, a treatment plan with measurable goals, and progress at each visit. Payers treat care that reads as maintenance, rather than correction, as not medically necessary.
Who this is for: California chiropractors and office managers billing Medicare, Medi-Cal, or commercial plans who are seeing denials for “not medically necessary.”
What “medical necessity” means to a payer
Medical necessity is the payer’s test for whether a service was needed to diagnose or treat a condition. For chiropractic, the test is narrow. Under Medicare, coverage requires a significant neuromusculoskeletal health problem, manipulation that has a direct therapeutic relationship to that problem, and a reasonable expectation of recovery or improved function.
The scale of the problem is published. A 2024 review by Medicare’s Comprehensive Error Rate Testing (CERT) program found errors in 33.6% of chiropractic claims, and CMS lists insufficient documentation as a common issue. CERT is the program Medicare uses to measure improper payments.
Your note is the only evidence a reviewer sees. A reviewer who wasn’t in the room can’t infer what you meant. If it isn’t written down, it didn’t happen.
The documentation gaps that trigger denials
1. A complaint of “pain” with no location or spinal level
This is the most basic gap. CMS states that a claim saying only that the patient feels pain isn’t enough, and you need to record where the pain is and which vertebra could be causing it.
Medi-Cal says the same thing more strictly. The diagnosis must show an anatomic cause of symptoms, such as sprain, strain, deformity, degeneration, or malalignment, and the spinal level must have a direct causal relationship to the symptoms. Medi-Cal also states that generalized or diffuse “pain” does not establish medical necessity on its own.
2. Subluxation that isn’t demonstrated
Subluxation is the spinal misalignment that chiropractic manipulation treats. Medicare needs proof it exists, by imaging or by exam.
For imaging, the x-ray must be taken within 12 months before or 3 months after treatment starts, and your record must show your review of the image and the level of subluxation.
For exam, Medicare uses the PART system. You need at least 2 of the 4 PART elements, and one of them must be asymmetry/misalignment or range of motion abnormality. The four elements are Pain, Asymmetry or misalignment, Range of motion abnormality, and Tissue tone changes.
The common failure: a note that documents pain and tissue tone changes only. That’s two elements, but neither is A or R, so it fails the test.
3. A missing or thin treatment plan
A treatment plan tells the payer what you expect to achieve and how you’ll measure it. CMS lists missing or inadequate treatment plans among the common claim denial reasons.
A plan that survives review states visit frequency and duration, specific treatment goals, and objective measures to evaluate whether treatment is working. “Patient will feel better” is not a goal.
4. Follow-up notes that don’t show change
Cloned notes, where every visit reads the same, are a denial trigger because they show no progress. Medicare expects each subsequent visit to include a review of the chief complaint, changes since the last visit, an exam with at least 2 PART elements, an assessment of change in the patient’s condition, and an evaluation of treatment effectiveness against the objective measures in the plan.
If your EHR template auto-fills yesterday’s findings, turn that feature off for exam fields.
5. Care that reads as maintenance
This is the trap that catches established practices. Medicare pays for correction, not upkeep. When further clinical improvement isn’t expected and treatment becomes supportive rather than corrective, Medicare classifies it as maintenance therapy and does not cover it.
Medi-Cal does not cover maintenance therapy either, and defines it as continued repetitive treatment without a clearly defined clinical end point. That definition is the key. If your plan has no end point, a reviewer can read the whole episode as maintenance.
Commercial payers apply similar logic. As one example, Kaiser Permanente’s Mid-Atlantic States policy (not California) treats additional visits as not medically necessary when goals are reached, benefit plateaus, or there’s no improvement within 14 calendar days and treatment isn’t modified. Check your California plan contracts for their specific criteria.
6. Billed regions that don’t match documented regions
Chiropractic manipulative treatment (CMT) codes are chosen by how many spinal regions you treat: 98940 covers 1 to 2 regions, 98941 covers 3 to 4 regions, and 98942 covers 5 regions. If you bill 98941, your note must name three or four treated regions. CMS lists failure to document all treated spinal regions as a common denial reason.
7. No response to a records request
When Medicare wants to review a claim, it sends an Additional Documentation Request (ADR). CMS states that failure to respond to an ADR is a major reason for claim denials. Assign one person to watch for ADR letters and log every deadline.
How the rules differ by payer type
| Payer type | What it covers | Key documentation rule |
|---|---|---|
| Medicare (Noridian, Jurisdiction E) | Manual manipulation of the spine to correct subluxation only | Subluxation by x-ray or PART exam, AT modifier for active care |
| Medi-Cal (fee-for-service and managed care plans) | Spinal manipulation, limited populations, 2 services per month | Diagnosis must show anatomic cause, no maintenance care |
| Commercial plans and benefit managers | Varies by contract | Plan-specific review forms and visit approvals |
Medicare. Coverage is limited to manual manipulation of the spine for subluxation. California is in Medicare’s Jurisdiction E, where Noridian handles Part B for Northern and Southern California. Noridian lists its Jurisdiction E chiropractic LCD (Local Coverage Determination) as retired as of 12/31/19, so the national Benefit Policy Manual rules above carry the weight. Confirm this in the Medicare Coverage Database before you rely on it.
You also need the AT (active treatment) modifier. Medicare requires the AT modifier to pay 98940, 98941, and 98942 for active or corrective treatment, and you should not use it for maintenance therapy. The modifier is not a shield: it doesn’t prove the service is reasonable and necessary, and a medical review can still deny the claim if the record doesn’t support active treatment. For care you expect Medicare to deny, CMS advises getting a signed Advance Beneficiary Notice of Noncoverage (ABN).
Medi-Cal. Most California chiropractors are surprised by how narrow this benefit is. State law excludes chiropractic as an optional Medi-Cal benefit, with exemptions. Exempt groups include pregnant individuals for pregnancy-related care, beneficiaries under 21, residents of skilled nursing facilities, and PACE enrollees, and the exclusion does not apply to services at Federally Qualified Health Centers (FQHCs) and Rural Health Clinics (RHCs).
Outpatient chiropractic is capped at two services per month, shared with acupuncture, audiology, occupational therapy, and speech therapy, and extra visits need a Treatment Authorization Request (TAR). This policy applies to both Medi-Cal fee-for-service and managed care plans, so CalOptima, IEHP, L.A. Care, and Health Net members fall under it too. Medi-Cal also publishes the ICD-10-CM diagnosis codes it will pay chiropractic claims against, including M99.00 through M99.05 (segmental and somatic dysfunction). Check the diagnosis against that list before you submit.
Commercial plans and benefit managers. Some plans route chiropractic through a specialty benefit manager such as American Specialty Health (ASH). With ASH, you send clinical documentation for peer review, either on its Medical Necessity Review (MNR) form or as copies of your medical records supporting the treatment plan. A peer reviewer returns a determination approving or denying services, and if you disagree with the approved visit count you can resubmit with additional clinical documentation for reconsideration. Check each patient’s plan to find out whether a benefit manager is involved before the first visit.
What a CO-50 on your remittance means
CO-50 is the adjustment code most practices see for this problem. CO means contractual obligation, so the loss sits with you, not the patient. Reason code 50 means the services are non-covered because the payer did not deem them a medical necessity.
A CO-50 is not always final. Work it in this order:
- Read the remark codes. The Remittance Advice Remark Codes (RARCs) next to the CO-50 tell you which policy the payer applied.
- Compare the chart to the policy. Check the seven gaps above against the notes for every date of service on the claim.
- Decide: correct or appeal. If the claim was coded wrong (for example, the region count didn’t match), correct it. If the note supports the service, appeal.
- Watch the deadline. For Medicare, you have 120 days from receipt of the initial determination to request a redetermination, and receipt is presumed 5 calendar days after the date on the notice. Medicare contractors generally issue a decision within 60 days. Medi-Cal and commercial appeal windows differ by plan. [VERIFY: Medi-Cal managed care and commercial appeal deadlines per plan before stating them.] cmsaha
You cannot add documentation after the fact to fix a weak note. An appeal succeeds on what was recorded at the visit.
Case study
Chiropractor Billing Case Studies
Pre-submission checklist
Run every chiropractic claim against this before it goes out:
- The chief complaint names the pain location and the related spinal level.
- Subluxation is shown by a qualifying x-ray or by at least 2 PART elements, one of them A or R.
- A dated treatment plan states frequency, duration, goals, and objective measures.
- Today’s note shows change since the last visit, measured against the plan.
- The plan has a clinical end point, and the episode does not read as maintenance.
- The CMT code matches the number of regions documented.
- Medicare claims carry the AT modifier only for active treatment, with an ABN on file where needed.
- Medi-Cal claims use a listed diagnosis code, the patient falls in an exempt group or setting, and the monthly visit count is within limits or a TAR is approved.
- Commercial claims have any required benefit manager approval before the visit.
How CNB helps
Claim N Billing is a family-owned billing team in Irvine. We started by fixing billing failures in our own non-emergency medical transportation company, and now bill for small California practices, including chiropractors. CNB reports a 98% clean claim rate and a 40% denial reduction across the practices we work with. Your results depend on your payer mix and documentation.
If CO-50 denials are showing up on your remits, see how our chiropractic billing services work, or have us review your recent denials. For a broader view of what drives denials, read our guide to common claim denial reasons, and if you’ve received a records request, see how to prepare for a payer audit.
Get a free billing audit and we’ll show you where your chiropractic documentation and claims are losing money.
This article describes payer requirements for general information. It is not legal or compliance advice. Verify current requirements with each payer and your compliance counsel.