A denial notice lands in the remittance, and the first instinct in a busy practice is usually to appeal it, or set it aside for later. Both can cost money: appealing a claim that only needed correcting wastes an appeal window, and setting a denial aside lets the clock run out while the claim is still fixable.
A denied claim is not automatically lost revenue, and it is not automatically recoverable either. What happens next depends on what the payer decided, whether the claim or the decision was wrong, and how much time is left on the clocks that started when the denial posted.
First, check what actually arrived
Not every unpaid claim is a denial. Before anything else, confirm which of two very different things you are holding.
A denied claim was adjudicated: the payer received it, reviewed it, and decided not to pay it, in whole or in part. It appears on the electronic remittance advice (the 835 ERA) or the explanation of benefits (EOB), with a reason code for why and a group code for who bears responsibility under the contract.
A rejected claim never reached adjudication: it failed a front-end edit at the clearinghouse or payer — a wrong member ID, a missing field, an invalid code — and was sent back before any payment decision. It has no ERA to appeal, because there is no decision to contest. Correct the data and resubmit.
That distinction decides the next step: a rejection goes back for correction, while a denial goes to a decision — is the claim wrong, or is the payer’s decision wrong?
Read the remittance before choosing anything
The remittance is the denial’s instruction sheet. The claim adjustment reason code (CARC) says why the payer did not pay — a missing authorization, a coding mismatch, a service the plan does not cover. The group code says how the unpaid amount is classified under the contract: contractual adjustment, patient responsibility, or another category.
Read both codes together before anyone touches the claim. The reason code tells you which fix to consider; the group code tells you whether billing the patient is even on the table. Jumping straight from “denied” to “appeal it” skips the step that distinguishes a quick correction from a weeks-long appeal — and appealing a claim that only needed correcting is a common way a fixable claim ages past its deadline.
For code-by-code detail, see our guide to claim denial codes (CARC and RARC). This article stays on the workflow: once you know what the codes say, what do you do?
The three responses, and how to choose between them
Almost every denial resolves through one of three responses. Choosing the right one is the central decision of denial work.
1. Send a corrected claim. Use this when the payer’s decision was correct on the facts as submitted, but the claim itself was wrong: a wrong code, a missing modifier, a transposed date. A corrected claim replaces the original claim with the right information — a fix to your own submission, not an argument with the payer.
2. File an appeal. Use this when the claim was right and the payer’s decision was wrong, or when documentation the payer did not have can overturn it — clinical notes supporting medical necessity, or plan language supporting coverage. An appeal contests a decision, with evidence attached.
3. Adjust or write off the balance. Use this when neither path applies: the service is genuinely not covered, the benefit is exhausted, or pursuing the claim costs more than any realistic recovery. Writing off a claim is a documented decision that closes the account honestly, instead of letting it sit in receivables pretending to be collectible.
The rule of thumb: if the claim was wrong, correct it. If the decision was wrong, appeal it. If neither can change the outcome, adjust it and record why. Either wrong choice burns the clock on the response that would actually have worked.
Our corrected claim vs an appeal comparison goes deeper on that choice.
The clocks that run at the same time
A denial starts more than one clock, and they do not wait for each other.
The first is the timely-filing clock. Every payer sets a deadline for receiving a claim, measured from the date of service, and it varies by payer and contract — there is no universal window. A rejected claim does not stop this clock, because the payer never received it. Left alone, a rejection can turn into a late-filing denial, which generally cannot be appealed back into existence. Medicare’s filing limit is one calendar year from the date of service; commercial and Medicaid windows are set by their contracts, so the number that matters is always the one in the payer’s contract for that claim.
The second is the appeal clock, also payer-specific and often short. As the Medicare example, a first-level appeal — a redetermination request to the Medicare Administrative Contractor — must be filed within 120 days of receipt of the initial determination. Commercial plans set their own windows, frequently shorter, so never carry the Medicare number over to a commercial denial. Calendar the deadline the day the denial posts.
The third is the corrected-claim window, which again depends on the payer: a corrected claim still has to land inside the payer’s filing and correction rules. Appeals also have levels — under Medicare, redetermination leads to reconsideration and then higher levels; commercial appeals generally run an internal appeal first, then an external review. Each level has its own deadline.
Denial work is time work: a denial left unworked for a month has spent a month of every clock it carries.
Can the patient be billed?
Whether the patient can be billed depends on the denial and the contract, and the group code is the starting point: a contractual adjustment is not patient responsibility, while a patient-responsibility classification may be, but only as the contract and the payer’s rules allow.
Do not default to billing the patient. Check the group code, the contract’s terms for that denial type, and whether the patient was properly notified where notification was required. Billing a patient for an amount the contract makes the practice absorb creates a second problem on top of the denial. When the answer is unclear, the claim stays with the payer dispute until responsibility is settled.
What happens if nothing happens
A denial that is never worked does not stay neutral. It ages in receivables, inflating money the practice appears to be owed but will not collect, and eventually passes every deadline attached to it — becoming a write-off by default rather than by decision. Worse, it hides its own cause: a pattern of authorization or coding denials that nobody categorizes will keep repeating on new claims.
That is why the last step of denial work is the record: what the denial was, which response was chosen, and whether it is recurring. Tracking denials by reason lets a practice fix the front end — verification, authorization, coding — instead of reworking the same denial monthly.
A workable denial routine
The workflow for each denial is short enough to run the same way every time:
- Confirm it is a denial, not a rejection, on the ERA or EOB.
- Read the reason code and the group code before choosing a response.
- Choose one response: corrected claim, appeal, or documented adjustment.
- Calendar every deadline the day the denial posts — filing, correction, and appeal.
- Decide patient billing only from the group code and the contract, never by default.
- Record the denial by reason, so repeat causes get fixed at the source.
Frequently asked questions
Is a denied claim the same as a rejected claim?
No. A rejected claim never reached adjudication — it failed a front-end edit and has no ERA, so fix the data and resubmit. A denied claim was adjudicated and decided, and requires a corrected claim, an appeal, or a documented adjustment.
How long do I have to appeal a denied claim?
It depends on the payer. Medicare’s first-level appeal (redetermination) must be requested within 120 days of receipt of the initial determination. Commercial plans set their own windows, often shorter — check the denial notice and the payer’s contract, and calendar the deadline immediately.
Should I send a corrected claim or file an appeal?
If the claim itself was wrong — a wrong code, a missing modifier — a corrected claim is usually the right tool. If the claim was right and the decision was wrong or unsupported, appeal. Appealing a claim that only needs correcting wastes the appeal window.
Can I bill the patient after a denial?
Only as the contract and payer rules allow. The group code is the starting point: a contractual adjustment is not patient responsibility. Never bill the patient by default; confirm responsibility from the denial and the contract first.
Conclusion
A denial is a decision point, not a verdict. Read the remittance, classify the response before acting, and work the claim inside its clocks — corrected claim when the claim was wrong, appeal when the decision was wrong, documented adjustment when neither can change the outcome.
If denied claims are piling up unworked, or the same reasons keep repeating, a review of the denial workflow itself is usually where the fix starts. Our denial management service covers that work end to end, and a free billing assessment is a straightforward way to see which denials in your receivables are still fixable — and which deadlines are closest.
