How to Read Your Explanation of Benefits (EOB) Statement

An EOB)" class="auto-link">Explanation of Benefits — commonly called an EOB — is one of the most important documents your health insurer sends you, yet most people either throw it away or file it without reading it. That is a costly mistake. Your EOB is a detailed record of how your insurer processed a claim, and buried in its columns and codes are clues that can help you catch billing errors, understand denied services, and build a winning appeal.

This guide explains every section of a typical EOB and shows you how to use it strategically.

What Is an EOB?

An EOB is not a bill. This distinction matters. The EOB is a summary statement your insurer sends after processing a claim. It shows:

• What your provider billed
• What your insurer paid (or refused to pay)
• What you owe the provider
• Why certain charges were reduced or denied

You typically receive an EOB by mail within 30 days of a claim being processed, or you can view it online through your insurer's member portal. Keep every EOB you receive — they are your audit trail.

Section-by-Section Breakdown

1. Patient and Member Information

At the top of every EOB you will find:

• Member name and ID: Verify this matches you or your covered dependent.
• Group number: Your employer's group plan identifier.
• Date of service: When you received the care or service.
• Provider name: The doctor, hospital, or facility that submitted the claim.
• Claim number: A unique identifier you will need for any appeals or follow-up calls.

Always verify these fields are accurate. An EOB with the wrong member ID, wrong provider, or wrong date of service signals a billing error that needs correcting before anything else.

2. Services Billed

This column lists each service or procedure as a line item, usually identified by a CPT code (Current Procedural Terminology) and a brief description. For example:

• 99213 — Office visit, established patient, moderate complexity
• 93000 — Electrocardiogram, 12-lead
• 90837 — Psychotherapy, 60 minutes

Check that the services listed match what you actually received. A charge appearing on your EOB for a service you never had is a billing error — and potentially fraud — that you should dispute immediately.

3. Amount Billed

This is what your provider originally charged. Providers often set rates above what insurers actually pay, based on negotiated contracts. The "amount billed" number is rarely what anyone actually pays.

4. Negotiated Rate / Allowed Amount

This is the contracted rate your insurer has agreed to pay for that service. It is almost always lower than the billed amount. The difference is called an adjustment and neither you nor your insurer actually pays it (assuming your provider is in-network).

If your provider is out-of-network, there may be no negotiated rate, and you may be responsible for the full difference between the billed amount and what your insurer covers.

5. What the Plan Paid

This column shows the dollar amount your insurer actually paid to the provider. Compare this to the allowed amount — the gap is usually covered by your deductible

• Co-pay: A flat fee per visit or service

Add up your responsibility columns across multiple EOBs and compare to your Explanation of Benefits year-to-date totals. Insurers sometimes apply charges to the wrong cost-sharing category.

7. Remark Codes and Adjustment Codes

This is the most important section for appeals. Every reduction or denial will have a Claim Adjustment Reason Code (CARC) and often a Remittance Advice Remark Code (RARC). These codes tell you exactly why the insurer reduced payment or denied a service.

Common examples:

• CO-45: Charge exceeds fee schedule / maximum allowable
• CO-97: Payment included in the allowance for another service
• PR-96: Non-covered charge; patient is responsible
• OA-23: Adjusted for a prior payer
• CO-4: Service inconsistent with the plan of treatment

Look up every code on your EOB at the Washington Publishing Company code lookup or simply Google "CARC [code number]." Understanding why a payment was adjusted or denied is the foundation of your appeal.

How to Spot Common EOB Errors

Billing errors are far more common than most people realize. As you review your EOB, watch for:

• Duplicate charges: The same CPT code billed twice on the same date
• Upcoded services: A simple office visit coded as a complex one
• Unbundled services: Procedures that should be billed together coded separately to inflate cost
• Services not rendered: Charges for procedures, tests, or supplies you did not receive
• Wrong diagnosis code: An incorrect ICD-10 code that triggers a denial or a coverage exclusion
• **coordination of benefits. ClaimBack uses the details of your denial to generate a customized appeal — fast, without a lawyer.

Start your appeal at claimback.app/appeal.

Related Reading

• How to Read an Explanation of Benefits (EOB)
• Claim Denied for Coordination of Benefits: How to Appeal
• What Is Coordination of Benefits? Dual Coverage Explained
• Coordination of Benefits Insurance Dispute: How to Appeal and Win
• VA Benefits Claim Denied? How to Appeal