An Explanation of Benefits is one of the most misunderstood documents in healthcare. Most people throw it away thinking it is a bill. It is not. It is a detailed record of how your insurer processed a claim, and it is worth reading.
By Naomi Foster, Healthcare WriterSpot a code on your EOB you do not recognize? Look it up here in seconds.
This explainer is for general education. If you have a specific question about your coverage or a billing dispute, your insurer or a patient advocate is the right contact.
An EOB (Explanation of Benefits) is a summary statement from your health insurer showing what was billed for a medical service, how much the insurer paid, what adjustments were applied, and what you owe (if anything). It is not a bill, but it tells you what to expect on any bill that follows.
The service date and provider field confirms which visit or procedure the EOB covers and who provided the service. If the name or date is wrong, flag it immediately: it may indicate a billing error or an identity issue.
The billed amount is what the provider charged. This is the starting figure before any insurance adjustments and is almost always higher than what anyone actually pays.
The contractual adjustment (sometimes called a discount) is the amount written off because of the provider's contract with your insurer. In-network providers agree to accept discounted rates; this line shows what was reduced.
The plan paid line shows what your insurer actually paid the provider after applying the adjustment. This is the insurer's share of the claim.
Your responsibility is what you owe, broken down into deductible, copay, coinsurance, and any non-covered charges. This number will appear on your bill from the provider.
If the claim was denied or paid at less than expected, the EOB will include a remark code (such as CO-97 or PR-96) explaining why. These codes determine whether an appeal makes sense.
Your EOB lists the CPT code(s) billed for each service line. These correspond to the specific procedures performed. If you see a code you do not recognize, look it up in the Code Lookup to see what service it represents, then compare it against what you actually received. Discrepancies can indicate a billing error.
Wrong service date, wrong provider name, a code for a service you did not receive, duplicate billing for the same service, or an in-network provider billed as out-of-network are the most common errors. If the billed codes do not match your actual care, call your provider's billing office first. If that does not resolve it, contact your insurer's member services.
Appeals have a clock on them, and it starts the day the EOB is issued, not the day you notice the problem. Read the remark code first: it tells you whether the issue is a documentation gap, a coverage exclusion, or a straightforward billing error, and that shapes what evidence you gather. Keep every EOB related to the claim; a pattern of similar denials across visits is often more persuasive to a reviewer than a single strongly worded letter.
If a claim is denied, the EOB will state the reason and your appeal rights. You generally have 30 to 180 days (varies by insurer) to file an internal appeal. If that fails, you may request an external review by an independent organization. Keep all EOBs: they are the paper trail for any dispute or appeal. See Common CPT codes explained to understand what codes were billed.
Spot a code on your EOB you do not recognize? Look it up here in seconds.
No. An EOB is a statement from your insurer showing how it processed a claim. The actual bill comes from your provider (a doctor, hospital, or lab). The EOB tells you what to expect on that bill, but it is not a request for payment itself.
Patient responsibility is the total amount you owe after your insurer has paid its portion. It is the sum of any deductible applied, your copay, your coinsurance, and any non-covered amounts. This is what your provider's bill will reflect.
Contact your provider's billing office immediately and ask them to review the claim. If the provider confirms an error, they can submit a corrected claim. If they dispute it, contact your insurer's member services and consider filing a grievance. Billing errors are common and fixable.
Keep EOBs for at least one year, or until all related bills are paid and disputes are resolved. For tax purposes (if you deduct medical expenses) keep them through the tax filing period. For any ongoing health issue, keeping a longer record is wise.
