Reviewed by Carola Cornejo
Key Takeaways
- A rejection stops a claim before payer review; a denial means the payer reviewed it and declined to pay.
- Hard denials are not recoverable; soft denials can be corrected, resubmitted, or appealed — and the distinction should drive triage decisions.
- Medicare Part A and B redeterminations must be filed within 120 days of the remittance advice date; most commercial payers set shorter windows.
- AR prioritization by age and dollar value prevents high-value claims from aging past filing deadlines while lower-priority denials consume staff time.
- Denial write-offs by category reveal revenue impact; denial rate alone measures volume without showing what is actually being lost.
Most billing teams have a working understanding of denial categories. The questions that slow down revenue recovery tend to be about process — what to do once a denial lands, how fast to act, whether an appeal makes sense, and how to keep a growing queue from aging out. This FAQ addresses those questions directly. Note: For background on the denial types that generate most of this work, see “Common Denials in Medical Billing: What They Are, Why They Happen, and How to Prevent Them.”
What is the difference between a rejection and a denial?
A rejection occurs before the claim reaches the payer for review. The clearinghouse or payer system flags a structural problem — missing required fields, invalid codes, incorrect payer ID, duplicate submission — and returns the claim without adjudicating it. The claim has not been processed; it needs to be corrected and resubmitted.
A denial occurs after the payer has reviewed the claim and made a payment determination. The payer received it, evaluated it, and declined to pay — for reasons ranging from medical necessity to missing authorization to coordination of benefits. Denials carry formal appeal rights with defined filing deadlines. Rejections do not, because no coverage determination has been made.
Rejected claims need to move quickly. They have not started the timely filing clock, but resubmission delays add unnecessary lag. Denied claims require a different response: pull the explanation of benefits or remittance advice, identify the reason code, and decide whether to correct and resubmit, appeal, or write off.
What is the difference between a hard denial and a soft denial?
A soft denial can be resolved — by correcting a coding error, supplying missing documentation, obtaining a retroactive authorization, or resubmitting with the right modifier. The claim is not permanently closed; it can move to payment with the right action.
A hard denial cannot be recovered. Services outside the patient’s coverage, claims past the timely filing window, and non-covered procedures are hard denials. Once the filing or appeal deadline passes, the revenue is gone regardless of how the claim is worked.
Hard denials should be written off and closed as soon as they are confirmed. Leaving them open distorts the AR aging report and makes recoverable denials harder to find. Soft denials drive the active work queue. Knowing which category a denial falls into at the point it is posted saves significant staff time over the course of a month.
How do we decide whether to appeal a denial or write it off?
Three factors drive the decision: the reason for the denial, the dollar amount, and whether the documentation supports reversal.
Reason code first. Some denials are correctable without a formal appeal — an eligibility denial on a claim where the patient had active coverage, a timely filing denial where records confirm submission within the window, or a coding denial where a modifier was missing but the service is documented. These are handled by correcting and resubmitting. A medical necessity denial based on the clinical record requires a formal appeal with supporting documentation, and the outcome depends on what the chart actually contains.
Dollar amount next. Every practice needs a minimum threshold below which appeals are not cost-effective given the staff time required. That number varies by practice size and payer mix, but it should be set explicitly — not decided claim by claim. Claims above the threshold with a defensible basis go to appeal. Claims below threshold for non-recoverable reasons get written off and coded by denial category for tracking.
Documentation last. An appeal for medical necessity without chart support has little chance of success regardless of how it is written. Before filing, the question is whether the record establishes the clinical indication, the decision-making process, and the appropriateness of the service. When the documentation is not there, the better use of time is fixing the upstream workflow to prevent the same denial from recurring.
What appeal filing deadlines do we need to track?
Timelines vary by payer and appeal level. Missing them forfeits the right to appeal regardless of the merits.
For Medicare Part A and Part B, the Level 1 redetermination must be filed within 120 days of the remittance advice date. Level 2 reconsideration by a Qualified Independent Contractor must be filed within 180 days of the redetermination notice. Level 3 — a hearing before an Administrative Law Judge — must be requested within 60 days of the Level 2 decision, and the amount in controversy must meet the annual threshold, which is 00 for calendar year 2026.
Commercial payers set their own timelines, and they are frequently shorter than Medicare. Many set appeal deadlines at 90 to 180 days from the remittance advice date; some are as short as 60 days. Payer contracts govern these windows, and they are not always stated clearly on the denial itself. Billing teams need to know the appeal deadlines for their highest-volume payers before a denial lands.
Appeal deadlines tracked in the practice management system — not in staff memory — is the operational standard. A denial flagged for appeal but not calendared is a denial that ages out.
How should we prioritize a denial work queue?
Two variables drive prioritization: age and dollar value. A claim approaching a timely filing or appeal deadline at any dollar amount takes priority over a newer claim at the same amount. A high-dollar claim within its appeal window takes priority over a lower-dollar claim at the same age. Both dimensions need to be visible simultaneously.
Most billing systems can be sorted by days outstanding and balance. The tier worked first is high-dollar claims within the last 30 days of their appeal or filing window, followed by high-dollar claims with time remaining, followed by everything else. Claims below the write-off threshold that have aged past the appeal window should be written off and closed rather than left open inflating the AR balance.
Denial reason codes add a third filter. Eligibility and authorization denials that trace to front-end failures are handled differently from coding denials requiring chart review or medical necessity denials requiring physician input. Routing by reason code category keeps work moving to the right person rather than sitting in a general queue.
In our work with practices managing high denial volume, the most common driver of aging AR is the absence of a triage system that distinguishes recoverable from non-recoverable denials at the point they are posted. Once that triage is in place, the queue becomes manageable. Practices evaluating how denial management fits into their larger revenue cycle may find value in reviewing PGM’s physician medical billing and RCM services.
What information is needed to file a successful appeal?
The core elements are consistent across denial types: the original claim, the remittance advice or EOB showing the denial reason code, and documentation that directly addresses why the claim was denied.
For medical necessity denials, the appeal needs the relevant portion of the clinical record — the office note, operative report, or diagnostic workup that establishes the indication for the service and the clinical reasoning behind it. The appeal letter should reference the payer’s coverage policy or local coverage determination by name where applicable and explain specifically how the documentation meets the coverage criteria. Vague appeals that restate the service without engaging the denial rationale rarely succeed.
For coding denials, the supporting documentation needs to show that the code or modifier submitted accurately reflects the service performed. If the denial is based on a bundling edit, the documentation needs to establish that the services were distinct and separately reportable. If it is based on a missing element, the appeal needs to include what was missing.
For authorization denials where authorization was actually obtained, the approval reference number and authorization documentation are the appeal. Where no authorization was obtained and one was required, recovery generally requires a retroactive authorization process — which not all payers offer.
Submit everything that supports the case at the first level. Evidence not included at initial appeal levels can be excluded from consideration at subsequent levels, and later-stage appeals are more resource-intensive for the same potential recovery.
What does a denial rate tell us — and what does it miss?
A denial rate measures how often claims are being denied relative to total claims submitted. It tracks volume and signals something about billing accuracy at the front end, but says nothing about revenue impact — which denial categories are driving the volume, at what dollar value, or whether the denials that matter most are being recovered.
A high denial rate concentrated in low-dollar eligibility corrections that resolve and pay within two weeks is a different problem than the same rate driven by medical necessity denials on high-cost services being written off. The aggregate numbers look the same; the revenue lost and the required response are not.
Denial write-offs by category is where the actionable information lives. Tracking which denial types result in unrecovered revenue, at what dollar value, against which payers — that breakdown shows where practice revenue is actually being lost rather than where claims are being interrupted. Denial rate as a standalone KPI is a useful pressure gauge; write-off analysis by reason code is what tells you where to focus.
Clean claim rate measures pre-submission accuracy; denial rate measures what happens after claims reach the payer. Both are needed for a complete picture of revenue cycle health, and both have blind spots the other does not cover.
Can a claim be denied after it has already been paid?
Yes. Payers conduct post-payment audits and can recoup payments they determine were made in error. Recoupment typically appears as an adjustment on a future remittance advice rather than as a denial on the original claim.
Providers have the right to appeal recoupment decisions through the same process that applies to initial denials, and the same documentation standards apply. The appeal deadline clock starts from the remittance advice date on which the recoupment appears — not from the original payment date — so tracking remittance adjustments with the same attention as initial denials is essential.
What is the difference between a corrected claim and an appeal?
A corrected claim is resubmitted when the original claim contained an error — a wrong code, missing modifier, or incorrect patient information. It replaces the original claim and is treated as a new submission by the payer. An appeal challenges the payer’s determination on a claim that was submitted correctly; it does not replace the original but asks the payer to reconsider its decision.
Submitting a corrected claim when the situation calls for an appeal — or vice versa — can reset or forfeit deadlines. If a claim was coded correctly and the payer denied it on medical necessity grounds, a corrected claim resubmission does not address the denial reason and may reset the timely filing clock without preserving appeal rights. Identifying which response is appropriate before acting protects both the deadline and the appeal pathway.
How long should a denial stay open before we write it off?
A denial should stay open as long as there is a realistic path to recovery within the applicable appeal window. Once the appeal deadline passes and no exception applies, the denial is not recoverable and should be written off and closed.
Leaving unrecoverable denials open distorts the AR aging report and makes it harder to identify where active recovery efforts belong. The write-off should be coded by denial reason category so the volume and dollar impact are available for trending. That data connects denial management to upstream workflow improvement — the categories with the highest write-off dollar values are where prevention efforts produce the most return.
How PGM Billing Supports Denial Management
Denial management is where revenue that was earned either gets collected or gets lost. PGM’s medical billing and RCM services include structured denial tracking, appeal workflows by payer and denial category, and root cause analysis to reduce denial volume over time. On the prevention side, pre-submission claim review catches coding and documentation issues before they reach the payer — reducing the denial volume that needs to be worked in the first place. If your practice is carrying aging denials or unsure whether your current write-off rate reflects recoverable revenue, contact us to find out how we can help.