Every year, the Department of Health and Human Services Office of Inspector General publishes its Work Plan — a list of the Medicare billing areas it intends to scrutinize through audits, investigations, and enforcement actions. Chiropractic has been on that list for multiple consecutive years.
If you're an independent chiropractor billing Medicare, the OIG Work Plan isn't an abstract policy document. It's a preview of where Medicare audit activity is headed — and in 2026, chiropractic billing is firmly in the crosshairs.
This guide explains what the OIG has identified as chiropractic billing priorities, what specific enforcement activity looks like, and what independent practices can do to reduce their audit risk.
Why Chiropractic Has Been an OIG Priority for Years
Chiropractic has one of the highest rates of improper Medicare payments of any specialty. The OIG's interest isn't punitive — it's driven by data showing that a significant portion of chiropractic Medicare claims don't meet coverage requirements.
The pattern the OIG has consistently found: practices billing for chiropractic services that either didn't meet Medicare's coverage criteria (active/corrective care for subluxation) or weren't supported by adequate documentation. In many cases, the care may have been clinically appropriate — the problem was documentation.
The OIG's Current Chiropractic Enforcement Priorities
Priority 1: AT Modifier Compliance
The AT modifier — which signals active/corrective care rather than maintenance therapy — is the most scrutinized element of chiropractic Medicare billing. The OIG has found that a substantial portion of chiropractic claims with the AT modifier aren't supported by documentation demonstrating active/corrective care.
Specifically, auditors look for claims where the patient has received extended treatment without documented functional improvement — suggesting the care transitioned to maintenance therapy, which Medicare doesn't cover, without the billing reflecting that transition.
Priority 2: Maintenance Therapy Billed as Active Care
This is closely related to AT modifier compliance. When a patient has reached maximum therapeutic benefit, Medicare coverage ends. Continuing to bill with the AT modifier after that point — billing maintenance therapy as if it were active/corrective care — is one of the most common violations the OIG identifies in chiropractic audits.
Key risk: The OIG has found this violation pattern most commonly in long-term Medicare patients who have been in treatment for years. Practices with high volumes of long-term Medicare patients have significantly elevated audit risk if those patients' records don't show clear documentation of continued active/corrective care rationale.
Priority 3: Subluxation Documentation Deficiencies
Medicare covers chiropractic only for the treatment of subluxation. Claims where the medical record doesn't adequately document subluxation — at a specific level, with associated clinical findings — are improper payments under Medicare's rules, regardless of whether the patient had a subluxation.
Priority 4: Upcoding of Spinal Manipulation Codes
Billing CPT 98941 (3–4 regions) or 98942 (5 regions) when documentation supports only 98940 (1–2 regions) is a pattern MACs look for in prepayment review. Code selection must match documented clinical findings and treatment — not just what was performed.
How OIG Enforcement Actually Works: The Audit Sequence
Understanding how chiropractic audits unfold helps independent practices appreciate the stakes. The sequence typically looks like this:
Step 1: Data Analysis
Medicare Administrative Contractors and the OIG use claims data analytics to identify practices with billing patterns that deviate from peers — unusually high utilization, code distributions that suggest upcoding, or long treatment courses without the expected taper. This analysis flags practices for further review without any human review of records yet.
Step 2: Probe Audit
The MAC requests records for a sample of claims — typically 20–40. An auditor reviews the documentation against Medicare's coverage criteria. The practice has no warning this is coming and limited time to respond.
Step 3: Findings and Extrapolation
If the probe audit identifies documentation deficiencies, the MAC calculates an error rate from the sample. That error rate is then applied — extrapolated — across all similar claims in the look-back period (up to three years). A 40% error rate on a sample of claims becomes a demand for 40% of three years' billing.
The math: A solo chiropractor billing $300,000 per year in Medicare with a three-year look-back has $900,000 in potential exposure. A 40% error rate — which is what OIG audits have found on average for chiropractic — generates a $360,000 recoupment demand. For a solo practice, that's existential.
Step 4: Repayment or Appeal
The practice can repay the demanded amount or appeal. The appeals process is lengthy — typically two to four years through all levels — and expensive if attorney representation is involved. Most practices settle at some point in the process.
Step 5: Referral for Further Investigation
If the probe audit findings suggest a pattern of fraudulent billing — not just documentation deficiencies — the case can be referred to the OIG for investigation. At this stage, civil monetary penalties and potential exclusion from Medicare become possible outcomes.
What Independent Practices Can Do Right Now
Conduct an internal documentation audit
Pull 20 random Medicare claims from the last 90 days and review the supporting documentation against Medicare's coverage criteria. Look specifically for: AT modifier support, specific subluxation level documentation, objective clinical findings, and functional improvement tracking. Identify gaps before an auditor does.
Review your long-term Medicare patients
These are your highest-risk cases for the maintenance therapy / active care distinction. For any Medicare patient who has been in active treatment for more than six months, review whether the documentation supports continued active/corrective care. If a patient has plateaued, document it and issue an ABN before the next visit.
Fix your SOAP note templates
Most chiropractic EHR templates weren't designed with Medicare compliance in mind. Add required fields for subluxation level (specific, not just region), objective findings for each region treated, functional status comparison to previous visit, and AT modifier rationale.
Know your MAC's current LCD
Your Medicare Administrative Contractor publishes Local Coverage Determinations for chiropractic services that tell you exactly what your MAC requires. Find the current chiropractic LCD for your MAC jurisdiction and compare it to your current documentation practices. MACs update LCDs — what you read two years ago may not reflect current requirements.
Monitor OIG Work Plan updates
The OIG updates its Work Plan throughout the year, not just annually. New enforcement priorities can emerge from completed audit findings. Staying current on OIG publications is part of running a compliant chiropractic practice in 2026.
OIG Enforcement Changes. Stay Ahead of It.
ChiropractorBillingClarity monitors OIG Work Plan updates, MAC LCD changes, and enforcement activity every month and delivers a plain-English brief to independent chiropractic practices. Know what's coming before it arrives.
Start for $247/month →The Bottom Line on OIG Chiropractic Enforcement
The OIG's sustained focus on chiropractic billing reflects a real and documented problem: a significant portion of chiropractic Medicare claims don't meet coverage requirements as documented. For the majority of practices where the clinical care is appropriate but the documentation is inadequate, this is a fixable problem.
The practices most at risk are those that continue doing what they've always done — billing Medicare without actively monitoring their documentation against current coverage standards. The compliance gap is real, but it's addressable for any practice willing to treat documentation as seriously as clinical care.
In 2026, with chiropractic on the active OIG Work Plan and MACs deploying more sophisticated prepayment review, the cost of ignoring the compliance gap is higher than it's ever been. The cost of closing it is an investment in documentation discipline — and, ideally, in staying current with the standards that govern every claim you submit.