Key Points
- The EOB lays out the arithmetic line by line: the billed charge, the allowed amount, the contractual write-off, what the plan paid, and what falls to the member.
- The same information reaches the practice machine-readable as an electronic remittance advice, which is what billing systems use to post payments against claims automatically.
- The dense value is in the adjustment codes - they say exactly why money did not arrive and what kind of fix, if any, exists.
Explanation of Benefits (EOB) Explained
After a payer processes a claim, it reports the outcome. The EOB lays out the arithmetic line by line: the provider's billed charge, the allowed amount under the contract, the contractual write-off between them, what the plan paid, and what falls to the member as copay, coinsurance, or deductible.
The same information reaches the practice in machine-readable form as an electronic remittance advice (ERA), delivered through the clearinghouse. The ERA is what billing systems use for payment posting - matching payments to claims automatically - while the EOB is the human-readable rendition, and the one members receive with the reassurance that it is not a bill.
The dense value is in the adjustment codes: standardized reason and remark codes explaining every dollar not paid - applied to deductible, exceeds authorized units, service not covered, duplicate claim. Reading these codes is the diagnostic skill of revenue cycle work; they say exactly why money didn't arrive and what kind of fix, if any, exists.
Reconciliation is where EOBs earn attention in an ABA practice: was every session on the claim paid at the contracted rate? Underpayments and quietly zero-paid lines hide inside mostly-paid remittances, and they only surface when posting compares payment to expectation line by line rather than in total.
Denied lines on an EOB start clocks - correction and appeal windows run from the remittance date - so the EOB queue is a workflow, not an archive. A practice's collection rate is largely determined by how quickly and completely someone works what the EOBs say.