An Explanation of Benefits — EOB — arrives after every claim adjudication. It is the insurer's official statement of what they paid, what they adjusted, and what the patient owes. Reading one correctly is a core skill for any dental billing specialist. Here's the anatomy of a typical dental EOB.
1. What an EOB actually is
An EOB is not a bill. It is an informational document sent to both the practice and the patient after a claim is processed. It details the billed amount, the allowed amount, the plan's share, and the patient's share. A mismatch between your ledger and the EOB is a signal that something went wrong — either with the claim or the posting.
2. Header section
At the top you'll find the patient name, member ID, group number, claim number, and date of processing. The claim number is critical — you'll need it for any follow-up calls. The processing date starts the clock on your right to appeal if something was denied incorrectly.
3. Claim lines
Each procedure is listed as its own line. For each line, you'll see: Billed (what you submitted), Allowed (the plan's contracted maximum), Plan Paid, Contractual Adjustment (the write-off you agreed to by being in-network), and Patient Responsibility. If any line shows zero in the Plan Paid column, look at the remark codes on the right.
4. Remark codes
Remark codes explain why a line was adjusted, denied, or pended. CO-4 means the service is not covered for that patient. CO-22 is a COB issue. CO-50 means not medically necessary — and usually requires an appeal with documentation. PR-2 and PR-3 are patient deductible and coinsurance, which are the patient's responsibility. Always cross-reference remark codes against the X12 published list.
5. Patient responsibility
The EOB shows what the patient owes — their copay, deductible, and coinsurance combined. This number should match your treatment estimate. If it's significantly higher, it's often a sign the deductible wasn't verified accurately before the visit, or the patient has already used their annual maximum.
6. What to do next
Once you understand the EOB: post the payment to the exact procedure lines (not a lump sum), write off the contractual adjustments, and bill the patient balance. If any line was denied unfairly, note the denial reason and appeal within the payer's timeframe — usually 90 to 180 days from the processing date.