How to read an Explanation of Benefits (EOB)

Find the 'Amount allowed' and 'Plan paid' columns. The denial column's reason code tells you exactly why a line wasn't covered.

Your Explanation of Benefits is not a bill. It’s a statement from your insurer showing how it processed a claim.

The columns that matter

Every EOB layout is slightly different, but the core columns are the same:

Amount billed: What your provider charged.
Discount or not-allowed amount: The difference between billed and the network negotiated rate.
Plan paid: What your insurer actually sent to the provider.
Your responsibility: What you owe after the plan payment.
Reason/remark codes: Why specific lines were reduced or denied.

Reading the reason codes

The reason code is the most important field for disputes. Look it up in the remark code lookup on your insurer’s website, or search the CARC/RARC code online.

Common codes:

CO-4: Covered by another payer first
CO-97: Service included in another service billed on same date
PR-1: Deductible — part of your annual deductible

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