Denial codes / CO-23

Denial code 23

CO-23: Adjusted for the other insurer's payment

Adjusted for a prior payer's payment.

What to doRead the EOB, then decide
Often recoverableUsually not

The letters in front matter. CO means the office can't bill the patient for the amount; PR means the patient may owe it. The same number can appear with either, so read both parts.

Why dental offices see it

  • Normal secondary-claim math after the primary paid.
  • The secondary applied the primary payment incorrectly.

What to do

  1. Compare the primary EOB with the secondary's calculation.
  2. If the math is wrong, call or appeal with both EOBs.

Stop it next time

Always attach the primary EOB to secondary claims.

How many CO-23 claims are in your report? The free check counts them, ranks them by dollars and deadline and drafts the letter. It runs in your browser; nothing is uploaded.

Run the free check

Plain-English paraphrase; the official code list is maintained by X12. Insurer rules vary; check the insurer's provider manual. Not legal advice.