How to Read an Explanation of Benefits, Line by Line

Confirm the basics first; a surprising share of problems live here.

• Patient name and member ID — is this even your claim?
• Claim number — quote it on every call.
• Date of service — must match the visit you remember.
• Provider — and whether the EOB flags them in-network or out-of-network.
• Processed date — appeal deadlines usually run from here, not from the visit.

• Amount billed / charges. The provider's list price. Almost never the number that matters.
• Plan discount / network savings. Billed amount minus allowed amount. Contractually written off — you can't be charged for it in-network.
• Allowed amount / eligible expense. The contracted maximum. Every downstream calculation uses this number.
• Not covered / non-covered. Services the plan excludes. A remark code says why.
• Deductible. The portion applied to your annual deductible. You owe it.
• Copay. A flat per-visit amount, often already collected at the desk.
• Coinsurance. Your percentage of the allowed amount after the deductible (e.g. 20%).
• Plan paid / payment. What the insurer sent the provider.
• Patient responsibility / you may owe. Deductible + copay + coinsurance + non-covered charges. This is the only number your bill should match.

Check the arithmetic yourself: allowed − deductible − coinsurance − copay should equal plan paid. If it doesn't, something was processed incorrectly.

Every reduction or denial carries a footnote code, explained in a legend on the back page. Common themes:

• Prior authorization was required and not obtained
• Service considered not medically necessary as coded
• Duplicate claim submission
• Coordination of benefits — the plan needs to know about other coverage
• Out-of-network provider
• Timely filing limit exceeded (a provider problem, not yours)
• Service exceeds the frequency the plan allows

Codes about paperwork — missing authorization, other-coverage questions, duplicate claims — are usually resolved with one phone call and a resubmitted claim, no appeal needed.

Most EOBs show year-to-date progress toward your deductible and out-of-pocket maximum. Two things to verify: that the running totals actually increased by this claim's amounts, and that nothing is being charged to you after you've hit the out-of-pocket maximum — past that point covered in-network care should be paid at 100%.

1. Right patient, right date, right provider.
2. Provider processed at the correct network status.
3. Allowed amount is present — not just the billed amount.
4. The math reconciles to patient responsibility.
5. Deductible and out-of-pocket running totals moved correctly.
6. The provider's bill equals patient responsibility, not a cent more.

Call the member services number on the EOB and reference the claim number. If the insurer confirms the processing was correct but you disagree, you have the right to an internal appeal, and if that fails, an independent external review. Appeal windows are typically 180 days from the EOB date — file in writing and keep copies.

If the issue is a coding mistake, the fastest fix is usually the provider's billing office submitting a corrected claim rather than a formal appeal.