Purpose
Understand what an EOB (Explanation of Benefits) is, how it's structured, and how to extract critical info to post correctly in Open Dental.
What is an EOB
The Explanation of Benefits is the document the carrier issues after processing a claim. It explains:
- Which procedures it covered and which it didn't
- How much the insurance paid
- How much the patient owes (patient responsibility)
- If anything was denied, the reason (denial code)
In standard X12 industry format, the EOB is transmitted as 835 (Electronic Remittance Advice).
The 6 critical columns of every EOB
| Column | What it means | Post in OD |
|---|---|---|
| Billed Amount (Charged) | What you charged for the procedure | Original procedure fee |
| Allowed Amount | What insurance considers reasonable (UCR or contracted) | Base for payment calculations |
| Deductible | How much applied to patient deductible | Patient responsibility |
| Coinsurance / Patient Responsibility | What patient pays after deductible | Patient bill |
| Paid Amount | What insurance paid | InsPayAmt in OD |
| Write-Off / Adjustment | What we write off (if in-network) | Adjustment in OD |
If numbers don't match, there's a posting error.
Concrete example
Patient with PPO plan. Procedure: D2740 Porcelain Crown. UCR charged: $1,200.
| Concept | Amount | How calculated |
|---|---|---|
| Billed Amount | $1,200.00 | What you charge |
| Allowed Amount | $900.00 | Insurance UCR for D2740 in-network |
| Write-Off | $300.00 | $1,200 - $900 (in-network adjustment) |
| Deductible applied | $50.00 | Patient hadn't met deductible |
| Patient pays 50% | $425.00 | ($900 - $50) × 50% (Major category) |
| Insurance pays 50% | $425.00 | ($900 - $50) × 50% |
Verification: $1,200 = $425 (paid) + $475 (patient: $50 deductible + $425 coinsurance) + $300 (write-off) ✓
Common denial codes
When a procedure is denied, carrier specifies reason with code (CARC/RARC). Most common:
| Code | Meaning | Action |
|---|---|---|
CO-29 | Time limit for filing expired | Late appeal or write-off |
CO-50 | Service not medically necessary | Appeal with narrative + X-rays |
CO-96 | Non-covered service | Check if write-off or bill patient |
CO-97 | Payment included in another service | Bundled — not billed separately |
CO-119 | Frequency limit met | Wait for next year or bill patient |
CO-151 | Insufficient documentation | Re-submit with correct attachment |
CO-186 | Level of care not authorized | Retroactive pre-auth or appeal |
PR-1 | Deductible | Patient responsibility — bill patient |
PR-2 | Coinsurance | Patient responsibility — bill patient |
PR-3 | Copay | Patient responsibility — bill patient |
Workflow to post an EOB in Open Dental
1Open the corresponding claim
OD → patient Account → find claim by DOS + Carrier.
2Click "Receive Payment"
Open Dental opens insurance payment dialog.
3Fill line by line
For each procedure on EOB:
- InsPayAmt: what insurance paid
- WriteOff: in-network adjustment (if applicable)
- DedApplied: deductible applied
- Status: Received
4Confirm check/ACH
Fill CheckNum or EFT trace number, payment date, total EOB amount.
5Verify match
Total InsPayAmt of all lines must match EOB check.
6Save → procedures marked as paid
Patient balance updates automatically.
claimprocs table grouped by ClaimPaymentNum — not in paysplits. If balance doesn't update, check there.