A rejected claim fails basic format or data checks and never enters the payer system. It can usually be corrected and resubmitted right away. A denied claim was processed but refused payment, so it needs investigation and often an appeal.
Track both separately. Rejections point to front-desk and data entry problems, while denials point to coding, authorization, eligibility or medical necessity issues.
Daily claim scrubbing and fast follow-up keep both numbers low.