Health insurance denial & claim adjustment codes

What health insurance denial code B13 means on your EOB

The plan says it already paid. If you are being billed anyway, this is a strong signal to ask for the remittance record.

What usually causes it

• Payment was already issued to the provider.
• The provider's accounting has not posted it.
• Payment went to a different provider entity.

The documents that decide it

• The plan's remittance advice showing payment.
• The provider's statement.
• The date and amount paid.

What to do next

Request the remittance advice from your plan and send it to the provider's billing office. This usually ends the matter.

This page explains what a code means. It is information, not advice — it does not tell you whether your specific claim should have been paid, and it is not legal, medical, or insurance advice. Your plan documents and your denial notice govern your situation.