Medical bill and EOB terms, explained simply

An EOB is a document your health insurance company sends after it processes a claim from your provider. It shows what was billed, what your plan allowed, what the plan paid, and what it calculates you may owe. An EOB is not a bill and isn't a request for payment — it's a record of how your insurer handled the claim.

The allowed amount is the maximum your insurance plan will recognize for a given service, based on its contract with the provider. If an in-network provider charges more than that, the difference is typically written off rather than billed to you. It's the figure the rest of the EOB's math is built from.

An adjustment is the portion of a provider's charge that gets reduced because of a contracted rate with your insurer — the gap between what was billed and the allowed amount. It shows up on your EOB, and often on your bill as its own line, so you can see it was never actually owed.

Patient responsibility is the amount your EOB calculates you may personally owe after insurance has processed the claim — generally the allowed amount minus what the plan paid. It's the insurer's figure; your provider's actual bill should reflect it, though timing differences between the two are common.

Some EOBs include this exact phrase to make clear the document is informational, not a request for payment. Its purpose is to stop people from paying an insurance document that was never asking to be paid — your bill, if one is owed, comes separately from your provider.

No. Your EOB comes from your insurance company and shows how a claim was processed. Your bill comes from your provider and is the actual request for payment — it can arrive separately, at a different time, and may lag behind your EOB if the provider hasn't caught up with a recent insurance adjustment yet.

An itemized bill lists every individual charge on your account — each service, supply, or procedure with its own code and amount — rather than one lump-sum total. It's the document you need to check for duplicate charges, wrong quantities, or services you don't recognize.

A CPT (Current Procedural Terminology) code is a standardized number identifying a specific medical service or procedure on a bill or claim. It's how providers and insurers communicate exactly what was done, and it's what lets you look up what a given line item actually represents.

The balance is what a provider's own billing system currently shows as outstanding on your account, after whatever payments and insurance adjustments it has processed so far. It can differ from your EOB's patient responsibility figure if the provider hasn't yet applied a recent insurance payment.

Coordination of benefits is the process insurers use when a patient has more than one health plan, to determine which plan pays first and how much each covers. Your EOB may reference COB if a claim involved more than one insurer.

A deductible is the amount you pay out of pocket for covered services before your insurance plan starts sharing costs. It resets on a schedule set by your plan, usually annually.

Coinsurance is the percentage split between you and your plan for covered services after your deductible has been met — for example, you paying 20% and your plan paying 80% of the allowed amount.

A copay is a fixed dollar amount you pay for a specific type of visit or service — for example, $30 for a primary care visit — regardless of the service's actual allowed amount. Unlike coinsurance, it doesn't depend on a percentage of the cost, and some plans apply it even before the deductible is met.

Prior authorization is approval your insurer requires before certain services, procedures, or medications are covered. If it wasn't obtained when required, a claim can be denied even if the service itself would otherwise have been covered.

In-network providers have a contracted rate with your insurance plan, which typically means lower allowed amounts and lower costs to you. Out-of-network providers have no such contract, which can mean higher costs, different coverage rules, or no coverage at all, depending on your plan.

Balance billing is when an out-of-network provider bills you for the difference between what they charged and what your insurance paid, on top of your normal cost-sharing. Federal protections under the No Surprises Act limit balance billing in many emergency and certain other situations — see what a formal dispute looks like if you believe you were improperly balance-billed.