These are treated as the same thing constantly, and they are not. One is a claim the payer never received. The other is a claim the payer received and refused to pay.
A rejected claim failed a format or data check before the payer processed it, usually at the clearinghouse, and was never adjudicated. A denied claim was received and processed, and the payer decided not to pay. Rejections are corrected and resubmitted; denials are appealed.
A rejection happens before adjudication. The claim failed a format, data or eligibility pre-check — usually at the clearinghouse, sometimes at the payer's front door. The payer never processed it, so there is no determination and nothing to appeal. You correct the error and resubmit.
A denial happens after adjudication. The payer received the claim, processed it, and decided not to pay. There is a formal determination, a remark code, and an appeal right with a deadline.
Because rejections are the ones that disappear.
A denied claim appears on your denial report and in your A/R. Somebody will probably notice it eventually. A rejected claim often shows as submitted in your practice management system while never having reached the payer at all — so it sits in no report, nobody chases it, and the timely filing clock runs the entire time.
This is one of the most common ways claims quietly cross a filing deadline, and it happens without any visible failure.
Pull your clearinghouse rejection report for the last 90 days and compare it against what your system shows as submitted. If there are rejections nobody actioned, those claims have been ageing invisibly.
Practices that have never run this check frequently find claims already past filing deadlines — which is unrecoverable money, but also a clear signal about whether rejection reports are being reviewed at all.
Send us a rejection report and an A/R aging report. We will tell you whether claims are being lost between your system and the payer, and what is still inside its filing window.
Request a free A/R review