How do I find unbilled surgical codes in our EHR exports?

Unbilled procedure codes typically hide in three places: add-on codes that weren't paired with primary procedures, modifier combinations that were flagged by scrubbers and never resolved, and procedures documented in operative notes but never translated to charge capture.

Surgical charge capture is the most complex area of healthcare billing because it involves multiple handoffs between systems that don't natively communicate: the OR scheduling system, the anesthesia documentation system, the operative note in the EHR, and the billing/practice management system. Each handoff is an opportunity for procedure information to be lost or incompletely transferred.

Add-on codes are the largest category of unbilled surgical charges. CMS correct coding initiative (NCCI) edits define specific add-on codes that must accompany primary procedure codes—they cannot be billed alone. When a surgeon performs a complex closure (CPT +13102) along with a primary skin lesion excision, the add-on code is only billable with the primary. If a billing staff member enters only the primary code and the add-on is mentioned in the operative note but not on the charge ticket, the add-on is lost. Common lost add-ons include wound closure complexity upgrades (+13xxx), additional levels in spine surgery, intraoperative nerve monitoring (+95940), and prolonged service codes.

Modifier issues are the second category. When a modifier is required—modifier 22 for increased procedural services, modifier 26 for professional component, modifier 59 for distinct procedural services—and the claim is flagged by the scrubber, the typical workflow is to route it to a hold queue. Claims in hold queues often age past follow-up, and many are written off without ever being reviewed by someone with the authority or knowledge to apply the correct modifier and resubmit. The OIG Work Plan consistently identifies surgical modifier appropriateness as a high-priority audit area.

The most significant hidden problem in surgical billing is the gap between the OR log and charge entry. Most hospitals have two separate systems: an OR scheduling/documentation system that captures what procedures were performed, and a billing system where charges are entered. These systems rarely have automatic reconciliation. The OR log may show that a surgeon performed four procedures during a case, but only three appear on the charge ticket. Without a systematic OR log-to-charge comparison, this gap is invisible.

Charge capture lag is a related issue that standard revenue cycle reporting doesn't surface. Charges should be entered within 24–48 hours of the procedure for optimal cash flow. When charge capture lags 5–7 days, timely filing deadlines become a risk for secondary payers, and the reconciliation window for OR-to-charge comparison shrinks because operative notes are not yet finalized. Most practice management systems report on charge volume by date of service, not by charge entry lag—hiding this timing problem entirely.

Implement an OR log-to-charge capture reconciliation process on a weekly basis. Export the OR case log (all procedures performed, by surgeon, by date) and the charge entry log for the same date range. Compare procedure count per case. Any case where the charge entry count is less than the OR log count requires immediate review. This process requires approximately 2–3 hours per week and typically recovers $15,000–$40,000 in unbilled charges monthly in a medium-volume surgical practice.

Build add-on code pairing rules into your claim scrubber. For every primary procedure code that has commonly associated add-on codes, create a scrubber alert that fires when the primary is billed without the expected add-on. The alert should route to a coder review queue, not a rejection—the question is whether the add-on was performed, not whether there is a billing error. If the operative note confirms the add-on procedure occurred, it can be added to the claim before submission.

Conduct a quarterly surgeon-specific charge capture audit. For each surgeon, compare the ratio of add-on codes to primary procedure codes over the quarter against specialty benchmarks. A spine surgeon performing multilevel fusions should have add-on code rates consistent with the number of levels performed. Surgeons with add-on code rates significantly below their peers are almost always experiencing charge capture failures, not performing simpler cases. Showing surgeons their individual data compared to peers creates immediate engagement with the charge capture process improvement.