Good news: The most common rejection reasons are also some of the easiest to prevent. If you've compiled a list of your top-10 denials, compare it with Medicare's so you can determine where you stand compared to other practices' most frequent denial reasons. Remember: In some instances, you may simply need to notify the payer why it was wrong in rejecting your claim. Not every insurance denial automatically means that your practice made an error. If you carefully scrutinize your remittance advance notices (which used to be called "explanations of benefits [EOBs]"), you may find you're sometimes wrong and so is the insurer. Each Medicare carrier lists its top-10 reasons for denying claims. The following denials represent the top-10 reasons, compiled by averaging data from nine different Medicare carriers: 1. Duplicate claim submission 2. Bundled services 3. Individual provider number and/or group number missing from 24k or 33 of the CMS-1500 claim form 4. The payer does not deem the diagnosis linked to the procedure a "medical necessity" for that procedure 5. Medicare is the secondary payer but is being billed as primary 6. Noncovered services 7. Patient is not a Medicare beneficiary 8. UPIN and name of ordering or referring physician are missing/invalid 9. Incorrect modifier use 10. Procedure is a "screening" service and therefore not eligible for payment.