Claim Rejection vs Denial: The Difference and What to Do Next

The difference between a claim rejection and a denial is whether the payer processed the claim. A rejected claim failed edits before processing, so it never entered adjudication: you fix the data and send it again as a new claim. A denied claim was processed and not paid, in whole or in part: you send a corrected claim, ask for reconsideration or appeal, following the payer's process and deadlines.

What is a claim rejection?

A rejection happens at the front door. The clearinghouse, or the payer's front-end system, checks the claim's format and data before it goes into processing. If the claim fails an edit, it is sent back.

Typical causes:

• A member ID, name or date of birth that does not match the payer's records.
• A missing or invalid field, such as an NPI, a payer ID or a place of service.
• A diagnosis or procedure code that is not valid on the date of service.
• A claim sent to the wrong payer, or for a plan that was not active.
• A formatting problem in the electronic file.

Rejections come back on acknowledgment reports. The 999 says whether the electronic file itself was accepted, and the 277CA claim acknowledgment says whether each claim was accepted or rejected, with a reason. A clearinghouse also sends its own rejection reports. Because a rejected claim never entered processing, it has no remittance and nothing to appeal.

What is a claim denial?

A denial happens after the payer has processed the claim. The claim passed the front-end edits, was adjudicated against the patient's benefits and the payer's policies, and the payer decided not to pay all or part of it.

Typical causes:

• No prior authorization on file.
• The payer judged the service not medically necessary.
• The service is bundled into another service on the claim.
• The plan does not cover the service.
• Another plan should pay first.
• The claim arrived after the filing limit.
• The claim duplicates one already processed.

The denial arrives on the remittance (the 835 ERA, or a paper EOB) with a group code, a claim adjustment reason code (CARC) and often a remittance advice remark code (RARC). Our guide to common claim denial reasons explains each cause and how to fix it.

Rejection vs denial, side by side

The last row is the one that costs money. A rejected claim that sits unfixed can quietly pass the payer's timely filing limit, and then a fixable rejection turns into a late-filing denial that is hard to overturn.

What to do after a rejection

1. Read the message on the acknowledgment or rejection report and find the field it names.
2. Fix the data at its source (the patient record, the insurance on file, the code on the encounter), not only on the claim, so the next claim is right too.
3. Send the claim again as a new original claim. Do not mark it as a corrected or replacement claim, because there is no processed claim to replace.
4. Confirm the new claim was accepted on the next acknowledgment report.
5. Do it quickly, because the filing clock generally keeps running until a claim is accepted.

Keep the acknowledgment reports for claims that were accepted. If a payer later says a claim arrived late, an accepted acknowledgment is often your proof that it was sent on time.

What to do after a denial

1. Read the group code, the CARC and any RARC on each denied line.
2. Decide whether the denial is right. If it follows from your contract, such as a bundled service, it is a contractual adjustment to write off, not a claim to fight.
3. If the claim had an error on your side, send a corrected or replacement claim the way the payer asks. A commercial payer often wants a replacement claim (claim frequency code 7) that names the original claim number, while Medicare handles many clerical errors through a reopening.
4. If you disagree with the decision, ask for reconsideration or file an appeal with the documentation that supports the claim, inside the payer's window.
5. Do not send the same claim again as a new original. It will usually come back as a duplicate.
6. Record the reason, so the cause can be fixed upstream.

Medicare's appeal process has several levels, starting with a redetermination by the Medicare Administrative Contractor, and each level has its own deadline. Commercial payers set their own steps in the contract and the provider manual. Check the current CMS guidance and your payer contracts before you choose a route.

Partial denials and other look-alikes

• Partial denial. The payer paid some lines and denied others. Work only the denied lines.
• An adjustment, not a denial. A reason code on a paid line may describe a routine contractual reduction or the patient's cost share. Not every reason code is a denial.
• A pended claim. The payer is holding the claim for more information, such as records. It has not been denied yet, so answer the request quickly.
• Nothing paid, nothing wrong. A claim processed with no payment because the allowed amount went to the patient's deductible is not a denial. The PR group code shows the balance belongs to the patient.

Both kinds of problem shrink with the same habits: checking eligibility, capturing data exactly and reviewing claims before they go. Our list of habits that reduce claim denials covers them in order.

Frequently asked questions

Does a rejected claim count as filed?

Generally no. A rejected claim never entered processing, so it usually does not count as received for the timely filing limit. Keep the acknowledgment reports for accepted claims, and check each payer's rules.

Can you appeal a rejected claim?

No. There is no decision to appeal, because the payer never processed the claim. Fix the error and send the claim again as a new claim.

Which is worse, a rejection or a denial?

A denial usually takes more work, because it needs a corrected claim, a reconsideration or an appeal, each with its own deadline. A rejection is faster to fix, but only if someone fixes it before the filing limit passes.

What is a clean claim?

A clean claim has no errors or missing information and can be processed without the payer asking for anything more. Clean claims pass the front-end edits and are not rejected, though a clean claim can still be denied on its merits.

Sources

• Medicare Claims Processing Manual, chapter 1 (sections 70 and 80), CMS
• Checking Medicare Claim Status (MLN3171902), CMS
• Medicare Claims Processing Manual, chapter 22 (group codes), CMS
• Medicare Claims Processing Manual, chapter 34 (reopenings), CMS
• Adopted Standards and Operating Rules (HIPAA transactions), CMS
• Claim Adjustment Reason Codes, X12
• RFI #1945: Replacement Claim CLP01, X12
• First Level of Appeal: Redetermination by a Medicare Contractor, CMS