Rejected vs. Denied Medical Claims: Differences and How to Resolve Each

If you handle medical billing, you have probably heard “rejected claim” and “denied claim” used as if they mean the same thing. They don’t.

A rejected claim generally has not been accepted for adjudication, often because it contains a technical, formatting, eligibility, or data-related problem identified during claim submission or front-end processing. A denied claim has been adjudicated, meaning the payer processed the claim or service and determined that payment should not be made as billed.

That distinction matters because the next step is different. A rejection usually calls for correction and resubmission. A denial may require a corrected claim, reconsideration or formal appeal, depending on the denial reason and the payer’s rules.

The exact terminology and workflow can vary among payers, clearinghouses and claim systems, so your billing team should always follow the specific payer’s instructions.

A rejected claim is a claim that was not accepted for adjudication, usually because it failed a technical, data or business-rule edit during submission or front-end processing.

This does not necessarily mean the claim never reached a payer’s systems in any technical sense. A payer may receive a claim electronically and reject it before it enters the adjudication process. The important distinction is that there has generally not been a full adjudication decision on the claim.

For example, a claim could be rejected because:

• The patient identification information does not match the payer’s records
• The member or policy number is invalid
• The billing or rendering provider information is missing or invalid
• The NPI is missing or incorrectly reported
• A required field is incomplete
• A procedure or diagnosis code is invalid for the submission
• A required modifier is missing
• The payer ID or electronic routing information is incorrect
• The claim fails a payer or clearinghouse edit

A rejected claim is therefore usually a submission problem that must be corrected before the claim can move forward.

Rejections are often easier to resolve than denials, but they should not be ignored. A rejected claim is not automatically harmless simply because it can be corrected quickly. If your billing team does not identify and correct it promptly, the claim may eventually run into the payer’s timely filing limit.

The goal is not simply to reduce the rejection rate. It is to identify the root cause, correct the claim accurately, resubmit it promptly, and verify that the corrected submission was accepted.

A denied claim has gone through the payer’s adjudication process, at least to the point where the payer makes a determination on the claim or service line, and the payer decides that the billed amount will not be paid as submitted.

A denial can result from many different issues, including:

• Medical necessity concerns
• Lack of required prior authorization
• Services excluded from the patient’s benefit plan
• Eligibility or coverage limitations
• Incorrect coding
• Bundling or modifier issues
• Duplicate claims
• Coordination of benefits problems
• Missing or insufficient documentation
• Timely filing
• Provider network or contractual requirements

Unlike a typical rejection, a denial represents a payment determination. That means the correct response is not automatically “resubmit the same claim.” Not every denial has the same appeal rights – payer rules, plan type, contract terms and the reason for the denial all matter.

This is the only place in this guide where this decision is explained. Use it for every denial, then move on to the relevant fix-it steps below.

“Denied” does not automatically mean “appeal.” The denial reason should determine the action. Always confirm the exact path against the specific payer’s provider manual, denial notice and contract – corrected-claim, reconsideration and appeal rules are not standardized across payers.

Rejection and denial are not always whole-claim events. A claim can contain several service lines, and a payer can reject, deny, adjust, or partially pay individual lines while accepting or paying others.

• Check the affected level first. On a rejection, the clearinghouse or payer acknowledgment (e.g., a 277CA) will identify whether the entire claim failed or only specific service lines or fields. On an adjudicated claim, the remittance advice shows a payment or adjustment status for each individual service line, not just an overall claim status.
• Do not touch lines that were not affected. Correcting or appealing a line the payer already accepted or paid can create a duplicate, delay the lines that were fine, or trigger a new rejection.
• Track resolution at the line level. A claim can show as “processed” in your system while one service line is still open for correction or appeal. Report and follow up at the line level so nothing gets closed out prematurely.

Handle a rejected claim systematically rather than simply resubmitting it repeatedly.

Start with the clearinghouse report, payer response, claim acknowledgment, or billing-system message. Look for the specific field or edit that caused the rejection — not just a general description like “claim rejected.”

Electronic claim systems return status, error, and rejection information that can point to a problem with patient information, eligibility, provider information, coding, claim formatting, required fields, payer routing, or authorization information. Use the payer or clearinghouse documentation to interpret the message rather than assuming every code means the same thing across systems.

Compare the rejected claim against reliable source information: insurance card, patient registration information, eligibility response, provider enrollment records, clinical documentation, or original encounter information. If the patient’s member ID appears incorrect, verify the number rather than simply changing a digit based on assumption.

Update the incorrect information in the billing system. Pay attention to related fields – a claim may contain more than one error, and correcting only the first problem may result in another rejection.

Before you send anything, verify:

• The payer’s specific corrected-claim submission method (portal, electronic, fax, or paper)
• The original claim reference or control number
• The applicable replacement, void, or frequency indicator required by the payer
• Whether attachments are required
• Whether the payer wants the correction flagged as a rejected/resubmitted claim rather than a “corrected claim” (these are treated differently by some payers)

There is no single universal method or frequency code – confirm the requirement with the specific payer’s provider manual or portal before you submit.

Send the corrected claim according to the payer’s or clearinghouse’s instructions, with the corrected claim identified appropriately when required.

Do not consider the problem solved merely because the claim was resubmitted. Track the new submission and verify it was accepted for processing:

Rejected → Corrected → Resubmitted → Accepted → Adjudicated → Paid or Denied

(Anonymized, illustrative example – field names and codes will vary by clearinghouse.)

A practice submits an 837 claim batch. The clearinghouse returns a 277CA (Claim Acknowledgment) report. On the report, staff locates:

1. The claim identifier – the patient control number the practice used, so the rejected claim can be matched back to the billing system.
2. The status code – a claim-status category and status code combination indicating the claim was rejected before adjudication, not denied.
3. The invalid field – the report points to a specific segment/element, for example the subscriber’s member ID field, showing it did not match payer records.

Staff verify the member ID against the insurance card and eligibility response, correct the field in the billing system, and resubmit. They then check the next 277CA (or equivalent status response) to confirm the corrected claim was accepted into adjudication, rather than assuming acceptance because nothing “bounced back.”

Denials require more analysis because the correct response depends on the reason for the payment decision.

Start with the remittance advice, EOB, claim status information or payer denial notice. Identify the denial reason, the adjustment reason code and remark code (when applicable), the affected service line, the amount denied, payer instructions, and the reconsideration or appeal deadline. Do not begin an appeal until you understand what the payer actually said.

Was the procedure coded incorrectly? Was authorization required and if so, was it obtained but not linked correctly? Does the plan exclude the service? Is additional documentation needed? Was the claim a duplicate? Was another insurer responsible? Was the claim filed after the deadline? The answer determines the appropriate next step (see the decision table above).

Depending on the denial, this could include clinical notes, operative reports, diagnostic test results, treatment plans, prior authorization records, referral documentation, corrected coding information, eligibility verification, medical necessity documentation, or a letter explaining the basis for the appeal. Only submitting documentation that is relevant and permitted by the payer’s process is not automatically better.

Follow the payer’s instructions carefully, including patient information, claim number, date of service, provider information, denial or adjustment information, the requested action and supporting documentation. If the payer requires a specific form or submission channel, use it.

Record the date submitted, submission method, confirmation number, payer response deadline, follow-up date and final outcome. A denial that has been appealed is not necessarily resolved – keep tracking it until it is paid, formally exhausted, written off according to policy or otherwise resolved.

(Anonymized, illustrative example – codes will vary by payer and claim.)

A practice receives an 835 electronic remittance advice (ERA). One service line on an otherwise-paid claim shows a $0 payment. Staff review:

1. The affected service line – only one CPT line on the claim is denied; the remaining lines paid normally, so only that line needs action (see “Claim-Level vs. Service-Line Outcomes” above).
2. The CARC – the Claim Adjustment Reason Code on that line indicates the service was denied for a specific category of reason, for example a missing or invalid authorization.
3. The RARC – an accompanying Remittance Advice Remark Code adds detail, for example pointing to which authorization field or number the payer expected to see.
4. The payer explanation and deadline – the remittance or an accompanying denial letter states the reconsideration or appeal deadline for that determination.
5. The selected response – staff check whether authorization was in fact obtained. If it was obtained but not linked to the claim, they submit a corrected claim referencing the authorization number, per the decision table above, rather than filing a full appeal.

Rejection information and remittance adjustment information are not the same thing, and billing teams need to read them differently.

A CARC describes why a claim or service line was paid differently from the amount billed. CARCs are part of the standardized X12 code set used in healthcare electronic transactions and can identify adjustments related to non-covered services, duplicate services, authorization, patient eligibility, submission or billing errors and other payment adjustments. See the official X12 Claim Adjustment Reason Code list for current codes and definitions. A CARC should be interpreted together with the rest of the remittance rather than treated as a standalone explanation.

A RARC provides additional information about an adjustment or remittance processing. RARCs can supplement a CARC’s explanation or convey an informational message about remittance processing. See the official X12 Remittance Advice Remark Code list for current codes and definitions.

A useful denial-analysis workflow is: Denial/adjustment information → CARC → RARC → payer policy → supporting claim documentation.

Where to find the rejection or denial reason:

• For a rejection: clearinghouse report, claim acknowledgment (e.g., 277CA), payer response, claim status response, or billing-system rejection message
• For an adjudicated claim: Electronic Remittance Advice (ERA/835), Remittance Advice (RA), Explanation of Benefits (EOB), payer claim-status information, or denial notice

A generic description such as “claim denied” does not tell your billing team how to fix the problem. The specific code, remark, payer instruction, and claim details determine whether the appropriate response is correction, resubmission, reconsideration, appeal, additional documentation or no further action.

Once the claim is corrected and accepted, it enters the payer’s normal processing workflow. The payer may adjudicate it, pay it, partially pay it, deny it, request additional information or return another rejection or processing error. Resubmission does not guarantee payment – it gives the corrected claim an opportunity to move through adjudication.

• If the claim is rejected again: do not repeatedly resend it without understanding the new rejection. Review the original rejection, the correction made, the new rejection message, related claim fields, and payer-specific submission requirements. A second rejection may mean the original issue was not fully corrected or that another error was identified.
• If the corrected claim is denied: the claim has moved from a submission problem to an adjudication problem. Return to the decision table above to choose a corrected claim, reconsideration, appeal, or another payer-directed resolution.

The process varies by payer and plan, but a typical workflow includes an internal appeal or reconsideration first. The payer reviews the original determination and any new information, which may involve claims-processing staff, clinical reviewers, medical directors, coding specialists, or other payer personnel. A successful reconsideration or appeal may result in the claim being reprocessed.

If the internal appeal is unsuccessful, review the payer’s next available step. Depending on the circumstances, this may include a higher-level appeal, external review (see the box below, where applicable), contractual dispute resolution, arbitration where contractually available, a payer complaint or regulatory process, or an administrative write-off when appropriate. Do not automatically transfer a denied balance to the patient – patient responsibility depends on the applicable benefit plan, payer rules, contract and the circumstances of the claim.

External review is a consumer/patient right, not a step in a provider’s claim-correction or appeal workflow, and it belongs in a separate box for that reason.

Under the Affordable Care Act, a patient (or their authorized representative) who has exhausted their health plan’s internal appeal may have the right to ask an independent third party to review the plan’s decision to deny payment or coverage. This is filed by the patient or their authorized representative – not the billing office and only applies to certain plans and certain types of adverse benefit determinations.

For plans that use the HHS-administered federal external review process, a four-month window generally applies after the date of receipt of the adverse benefit determination or final internal adverse benefit determination. Other plans use a state external review process instead, which can have different requirements. See CMS’s official guidance: HHS-Administered Federal External Review Process and CMS External Appeals overview.

If a patient asks your office about this process, direct them to their plan’s denial notice (which is required to explain their appeal rights) rather than assuming the same deadlines or process used for provider appeals apply.

One of the easiest ways to lose otherwise recoverable revenue is to confuse a timely filing deadline with an appeal deadline. They are different, and both should be logged the moment a rejection or denial is identified – not when your team gets around to working the claim.

Deadline tracking log – fields to capture for every rejected or denied claim:

One of the easiest ways to lose otherwise recoverable revenue is to confuse a timely filing deadline with an appeal deadline. They are different, and both should be logged the moment a rejection or denial is identified – not when your team gets around to working the claim.

Deadline tracking log – fields to capture for every rejected or denied claim:

Medicare example (labelled as an example only – do not apply these figures to commercial, Medicaid, or Medicare Advantage claims):

• For Original Medicare fee-for-service claims, CMS generally requires claims to be filed no later than one calendar year after the date of service, subject to limited exceptions (CMS Medicare Claims Processing Manual guidance on timely filing). CMS also treats a Medicare claim denied solely for late filing as not an initial determination, and it is not subject to appeal.
• For Medicare fee-for-service claim determinations that are appealable, the first level of appeal is a redetermination, and CMS currently allows 120 days from receipt of the initial determination to request it (CMS: First Level of Appeal — Redetermination by a Medicare Contractor).

These Medicare rules are an example only. Always check the requirements that apply to the specific commercial payer, Medicare Advantage plan, or Medicaid program on the claim in front of you.

• Example 1: Incorrect Patient Information. A claim is submitted with an incorrect member ID and fails the payer’s front-end edits, so it is rejected. What to do: verify the member ID against the patient’s insurance information, correct the claim and resubmit per the payer’s requirements.
• Example 2: Missing Prior Authorization. A procedure requires prior authorization, but the claim does not contain it, or authorization was never obtained. The payer adjudicates the claim and denies payment under its authorization policy. What to do: determine whether authorization was actually obtained, whether the payer permits retroactive authorization, and whether reconsideration or appeal is available.
• Example 3: Medical Necessity Denial. A service is submitted with supporting diagnosis information, but the payer determines the documentation does not support the billed level of service under its medical-necessity policy. What to do: review the payer’s denial reason and policy, then determine whether additional documentation supports reconsideration or appeal.
• Example 4: Duplicate Claim. A practice accidentally submits the same claim twice; the payer identifies the second submission as a duplicate. What to do: verify which claim was processed or paid, follow the payer’s instructions, and do not automatically resubmit the duplicate again.

• Resubmitting without fixing the problem. Sending the same rejected claim again does not solve the underlying issue – identify the exact rejection reason first.
• Appealing without reading the denial. A generic appeal that doesn’t address the payer’s stated reason is unlikely to succeed.
• Treating every denial the same way. A duplicate denial, an authorization denial, a medical necessity denial, and a coding denial each require a different investigation.
• Missing deadlines. A clinically valid claim can still become uncollectible if the filing, reconsideration, or appeal deadline is missed – track each one independently using the framework above.
• Submitting too much or irrelevant documentation. Provide only what’s relevant to the payer’s stated issue.
• Confusing an EOB with a medical bill. An EOB explains how an insurer processed a claim – amounts billed, allowed, paid, and potentially assigned to patient responsibility – but it is generally not itself a bill.
• Assuming every payer uses the same process. Corrected-claim requirements, appeal levels, reconsideration procedures, filing deadlines, documentation requirements, submission methods and claim-status terminology all vary by payer – verify for the specific payer and plan.

• For rejections, focus on: accurate patient registration, eligibility verification, correct payer selection, provider enrollment information, clean claim edits, accurate coding, required modifiers, complete claim fields and automated claim-scrubbing rules.
• For denials, focus on: prior authorization workflows, medical necessity documentation, payer policy monitoring, coding accuracy, coordination of benefits, timely filing controls, denial trend analysis, appeal tracking and staff education.
• Track the root cause. A useful denial-management report goes beyond the total number of denials. Track the number of rejected and denied claims, denial and rejection rates, dollar value of denials, top denial reasons, payer-specific trends, average days to resolution, appeal success rate and write-off rate. This helps identify whether the underlying problem is registration, coding, authorization, documentation, payer behavior, or another process issue.

Rejected and denied claims both interrupt the revenue cycle, but they are not the same problem. A rejected claim generally has not been accepted for adjudication, so the priority is identifying and correcting the submission problem. A denied claim has been adjudicated and resulted in a payment determination, so the next step is understanding why the payer denied it and choosing correction, reconsideration, appeal or another resolution path from the table above.

The most effective billing teams identify the exact status, determine the root cause, follow the payer’s rules, track applicable deadlines at the line level, and document every action. That approach reduces avoidable rework, improves accounts receivable visibility and helps practices recover reimbursement that might otherwise be lost.

Rejected and denied claims can quickly become a recurring revenue-cycle problem. Revix MD helps healthcare organizations identify denial root causes, analyze payer trends, improve claim follow-up workflows and track unresolved claims more effectively. Request a free quote.