Billing terms explained.

Plain-English definitions for terms that show up on bills, EOBs, and denial letters. Written for patients — not insurance professionals.

• Explanation of Benefits (EOB)

  A statement from your health insurer showing how a claim was processed — not a bill, but the reason code tells you why something wasn't covered.

• Prior Authorization

  Approval from your insurer before receiving a service — required for many procedures, medications, and referrals. Skipping it is the most common reason for a preventable denial.