Most billers read an EOB to post payments. Check the allowed amount, post the payment, move on. Done in 60 seconds.

Payer auditors read the same document to find money. They’re looking at what the payer kept — and whether they had the right to keep it.

That’s the gap. And it’s costing your practice real money on claims that were already “processed.”

Starting today, slow down on your EOBs. Here’s what to look for.

5 Things to Check on Every EOB — Before You Post

Check 1

Contractual Adjustment vs. Actual Contract

The CO-45 adjustment — Charges exceed your contractual amount — gets accepted at face value every single day. Don’t. Pull your contract. Does the allowed amount match your fee schedule for that payer and that CPT? If you don’t have your fee schedule on file, that’s your first problem to fix.

Check 2

CO vs. PR Codes — Who Owes What

CO (Contractual Obligation) adjustments are write-offs. PR (Patient Responsibility) codes mean the patient owes it. Confusing these is a billing error and a compliance risk. Scan every adjustment line. If CO-45 and PR-1 appear on the same claim, verify the math adds up to your billed amount — it should.

Check 3

Allowed Amount vs. Billed Amount — Flag the Gap

When the allowed amount drops significantly below your billed rate and there’s no modifier attached, dig into it. Payers routinely underprice based on incorrect procedure mapping or outdated fee schedule data. If it happens once, it’s an anomaly. If it happens on the same CPT repeatedly — you’re looking at a systemic underpayment.

Check 4

Bundling Flags (CO-97 / CO-B15)

CO-97 means the service is included in another allowance. Sometimes that’s correct. Often it’s not. Cross-reference the bundled CPT against NCCI edits. If an unbundling modifier applies — 59, XE, XS, XU, XP — and wasn’t on the claim, that’s a corrected claim waiting to happen.

Check 5

Zero Pays That Shouldn’t Be

An EOB line with a $0.00 payment and no denial code is a data entry ghost — and payers produce them more often than you think. These can represent services that weren’t adjudicated at all. If you don’t catch it here, that revenue disappears without a trace.

Your EOB Audit Checklist — Clip This

  • CO-45 allowed amount matches your contracted fee schedule for that payer + CPT
  • CO vs. PR codes correctly applied — no confusion between write-off and patient balance
  • Allowed amount vs. billed flagged on recurring CPTs — pattern check
  • CO-97 bundles verified against NCCI — modifier opportunity identified?
  • Zero-pay lines with no denial code — pulled for adjudication review
  • Every denial has a valid, documented reason code — no orphan codes
Coming in Issue 10

Payer Underpayments: The Full Playbook. What we covered today is the detection layer. Issue 10 goes deeper — how to build a payer underpayment log, what triggers a formal dispute, and how to write an appeal that payers can’t shrug off.

For the complete EOB audit workflow — including fee schedule comparison templates, CO-97 NCCI quick reference, and underpayment tracking log: Denial Management Playbook →

Pay attention. Go get your money.
— CleanClaimRx
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