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Denial Management Workflow Guide
A source-backed workflow guide for billing companies managing denials, appeals, recovery work, and payer adjustment context.
Short answer
A denial management workflow for a billing company has six stages: intake from the 835 ERA, triage by CARC group code and dollar value, investigation against eligibility and documentation, decision (correct and resubmit, appeal, or write off), execution with documented packet, and recovery tracking. The CARC group code (CO, PR, OA, PI) determines who is responsible for the adjustment, which determines whether the next action is appeal, patient bill, or contractual write-off. Per the MGMA 2024 Cost and Revenue Report, the average initial claim denial rate is 11.8 percent; per the Experian Health 2025 State of Claims survey, 41 percent of providers see 10 percent or higher denial rates. The denial work that recovers revenue is structured, code-aware, and packet-ready; the denial work that loses revenue is a spreadsheet of "follow up later" items.
The denial environment is getting harder
A few numbers that frame why this work matters more in 2026 than it did three years ago:
- Average initial claim denial rate: 11.8 percent in 2024, up from 10.2 percent a few years earlier, per the MGMA 2024 Cost and Revenue Report
- 41 percent of providers now face denial rates of 10 percent or higher, per the Experian Health 2025 State of Claims survey
- Commercial plan denials rose roughly 1.5 percent year over year
- Medicare Advantage denials spiked roughly 4.8 percent year over year
- MDaudit network data shows average denied amounts rose 12 to 14 percent year over year for inpatient and outpatient claims
The practical takeaway: denial work is no longer a side workflow. For most billing companies, it is the single biggest lever between break-even and profitable client retention.
Understanding CARC and RARC codes
The 835 ERA carries the payer's reason for adjustment as a paired CARC (Claim Adjustment Reason Code) and optionally an RARC (Remittance Advice Remark Code). The CARC tells you the category of the adjustment. The RARC explains the specifics. Both are maintained by X12.
Every CARC pairs with a two-letter Group Code that determines responsibility:
| Group Code | Meaning | Typical next action |
|---|---|---|
| CO | Contractual Obligation — payer or contract terms reduced the payment | Adjust as contractual; do not bill the patient |
| PR | Patient Responsibility — the amount belongs on the patient bill | Move to patient statement workflow; not an appeal |
| OA | Other Adjustment — non-standard adjustment | Investigate; may require appeal or correction |
| PI | Payer Initiated Reductions — payer-internal adjustment | Usually informational; verify per payer policy |
The single most common denial-workflow mistake is treating PR codes as appealable. PR-1 (deductible) and PR-2 (coinsurance) are not denials at all; they are amounts to collect from the patient. The action item is moving the balance to the patient statement workflow, not writing an appeal to the payer.
The CARCs every billing company sees most
These are the codes that account for most of the denial volume, per industry summaries from X12, the FCSO Medicare guidance on CARC CO-97, and the Sprypt 2025 CARC and RARC guide:
| CARC | Plain English | First investigation step |
|---|---|---|
| CO-4 | Procedure code inconsistent with the modifier used | Verify modifier against the CPT and payer rules; correct and resubmit |
| CO-11 | Diagnosis inconsistent with the procedure | Recheck linking; corrected claim if documentation supports the procedure |
| CO-15 | Authorization number missing, invalid, or not applicable | Pull the authorization; resubmit with the correct number or appeal with documentation |
| CO-16 | Claim or service lacks information or has submission errors | Read the paired RARC carefully; the RARC tells you what is missing |
| CO-22 | Care may be covered by another payer (COB) | Verify primary payer; resubmit with correct COB information |
| CO-29 | Time limit for filing has expired | Verify timely filing policy; if within limit, appeal with proof of original submission |
| CO-45 | Charge exceeds fee schedule or maximum allowable | Contractual adjustment; verify contracted rate against expected |
| CO-50 | Non-covered service per medical necessity | Appeal with documentation if medically necessary; otherwise write off or bill patient per ABN |
| CO-97 | Benefit included in payment for another service (bundling) | Verify NCCI edits; appeal with modifier 59 or other unbundling justification if appropriate |
| CO-109 | Claim not covered by this payer | Verify correct payer; resubmit to correct payer |
| CO-197 | Precertification or authorization absent | Obtain retro-authorization if possible; appeal with documentation |
| CO-198 | Precertification or notification exceeded | Verify cap and timing; appeal with documentation if within policy |
| PR-1 | Patient deductible | Move to patient statement workflow; not an appeal |
| PR-2 | Patient coinsurance | Move to patient statement workflow; not an appeal |
| PR-3 | Patient copay | Verify copay was collected; move to statement if not |
The right denial workflow recognizes each of these on sight, routes by group code automatically, and uses the CARC and RARC pair to pre-populate the investigation step.
What should a denial workflow include?
| Layer | Purpose | What a good system surfaces |
|---|---|---|
| Intake | Capture every denied or adjusted line from the 835 ERA with CARC, RARC, group code, and dollar amount | One queue, not a per-payer report; sortable by code, payer, age, and dollar value |
| Triage | Sort by group code, payer, practice, financial impact, deadline, and ownership | Filter by CO versus PR versus OA so that patient-responsibility lines do not clog the appeal queue |
| Investigation | Pull eligibility at the time of service, authorization status, coding context, payer rules, and prior follow-up history | One screen with the claim, the ERA detail, the eligibility check, the auth, and the chart context |
| Decision | Choose correct and resubmit, appeal with documentation, adjust per contract, or bill the patient | Decision is logged with reason; future ERAs reference the prior decision |
| Execution | Build the appeal packet (medical necessity progress notes, prior conservative care, imaging, lab results) or resubmit the corrected claim | Packet templates by CARC category save thirty minutes per appeal |
| Recovery tracking | Track payer response, payment result, or closure reason | Pattern analysis by CARC, payer, provider, and code so future submissions avoid the same denials |
How long do you have to appeal?
Appeal timelines vary by payer and contract, but useful baselines per published payer policies:
- Medicare: 120 days from the initial determination for redetermination; longer windows for higher appeal levels
- Most commercial payers: 60 to 180 days from the date of the denial
- Medicaid: state-specific; usually 90 days, can be shorter
- Workers' compensation: state-specific; can be as short as 30 days
The 277CA acknowledgment date is the start of the clock for most payers, not the date you noticed the denial in the system. A denial workflow that does not surface aging by appeal deadline is missing the most important triage signal.
Where does Medi fit?
Medi presents denial work as an operating queue that connects 835 ERA lines, claims, remittance context, appeals, recovery items, underpayment flags, and account ownership. The honest claim is not that Medi eliminates denials. The useful claim is that denial work should be visible, filterable by CARC and group code, packet-ready, and traceable across attempts and outcomes.
What Medi will not claim:
- Denial elimination
- Recovery guarantees on any given denial
- Automatic appeal generation without human review
- Universal payer rule coverage (payer rules change faster than any vendor can keep up)
What should buyers verify in a denial workflow demo?
- Can denial lines be filtered by CARC, RARC, group code, payer, practice, age, owner, and dollar value, in any combination?
- Does the workflow distinguish rejection (277CA pre-acceptance failure) from denial (835 post-adjudication denial) from underpayment from contractual adjustment?
- Are CARC and RARC codes translated to plain English alongside the raw codes, or buried in payer-specific PDFs?
- Can a denial specialist build a documentation packet from inside the workflow without leaving the system?
- Does the system track appeal status with payer reference numbers and next-action dates?
- Can a manager see denial patterns by CARC, payer, provider, and code without exporting to a spreadsheet?
- Are PR codes routed to patient statement workflows automatically, or do they sit in the appeal queue?
Frequently Asked Questions
What is the difference between a rejection and a denial?
A rejection happens before the payer adjudicates the claim. The 277CA acknowledgment carries the rejection reason; the claim never enters the payer's adjudication system. A denial happens after the payer adjudicates and decides not to pay (or to pay less than expected); the 835 ERA carries the denial with CARC and group code. Rejections usually require a correction and resubmission; denials usually require an appeal or contractual adjustment.
What is the most common appealable denial code?
CO-97 (bundling), CO-45 (charge exceeds fee schedule), CO-50 (not medically necessary), CO-197 (no authorization), and CO-16 (missing information) account for most appealable denial volume in commercial billing. Each has a different first-action profile: CO-97 requires unbundling justification or modifier 59 review; CO-45 is usually a contractual write-off unless the contracted rate is wrong; CO-50 requires medical necessity documentation; CO-197 requires retro-authorization or an appeal with documentation; CO-16 requires reading the paired RARC carefully.
Can software auto-appeal denials?
Software can draft an appeal packet, pre-populate fields from the claim and ERA, and queue the appeal for staff review. Software should not file appeals without human review, because appeal letters frequently require nuance (medical necessity language, contract reference, specific payer policy citation) that AI gets wrong often enough to matter. The right pattern is software accelerating the appeal preparation, not software replacing the appeal preparation.
How fast should denials be worked?
Industry best practice is working denials within 7 to 14 days of receipt for high-dollar or time-sensitive denials, and within 30 days for lower-priority items. The constraint is appeal deadline, which varies by payer; Medicare gives 120 days, most commercial payers give 60 to 180 days, Medicaid varies by state.
How does Medi help with denial pattern analysis?
Medi surfaces denial volume by CARC, by payer, by provider, by practice, and by code over time. The pattern view is intended to inform front-end intervention (eligibility, authorization, coding, documentation) so the same denials stop happening, not just to track them after the fact.
How current is this guide?
Last reviewed 2026-05-17. CARC and RARC code definitions are maintained by X12. Denial statistics are drawn from the MGMA 2024 Cost and Revenue Report and the Experian Health 2025 State of Claims survey. CMS remittance guidance is at Health Care Payment and Remittance Advice.
References
These public sources provide background for standards, terminology, or competitor context discussed on this page.
- CMS Health Care Payment and Remittance AdviceCenters for Medicare and Medicaid Services
- X12 external code listsX12
- Experian Health 2025 State of Claims survey press releaseExperian Health
- MGMA detecting and fixing leaks across the revenue cycleMedical Group Management Association