What sets ASC billing apart
ASC billing covers the facility side of an outpatient surgery: the operating room, nursing staff, supplies, many drugs and most implants. Medicare pays the center a single facility rate per covered procedure, while the surgeon, anesthesia provider and pathologist each bill their own professional claims. A clean case needs all of those claims to describe the same procedure on the same date.
For Medicare, an ASC bills the facility fee on the 837P professional format (or, rarely, the CMS-1500), and the SG modifier has not been required on facility claims since 2008. Some commercial payers instead require the institutional 837I/UB-04 format for ASC facility claims, so the claim build follows each contract. Our medical billing services for surgery centers set those payer rules up once in the charge build.
Facility vs professional claims in ambulatory surgery center billing
| Item | ASC facility claim | Surgeon's professional claim |
|---|---|---|
| What it pays for | Facility resources: room, staff, supplies, many drugs and packaged items | The surgeon's work, under the physician fee schedule |
| Medicare claim format | 837P (CMS-1500 in rare cases) | 837P |
| Rate basis | ASC payment system, by payment indicator | Physician fee schedule facility rate |
| Typical additions | Separately payable drugs, radiology or devices where the indicator allows | Assistant-at-surgery and global period modifiers |
Ambulatory surgery center billing errors often start when the facility and the surgeon code from different documents. We code the facility claim from the signed operative report and compare it with the surgeon's codes, so a mismatch is resolved before either claim is sent.
ASC coding: payment indicators and rules specific to this specialty
ASC coding starts with CPT and HCPCS codes, but Medicare payment also depends on each code's ASC payment indicator, published in the quarterly ASC addenda. Indicators show whether a procedure is on the covered list, how its rate is set, and whether an ancillary item is paid separately or packaged.
| Indicator | Meaning (summary) |
|---|---|
| A2 | Surgical procedure on the ASC list in CY 2007; payment based on OPPS relative payment weight |
| G2 | Non-office-based surgical procedure added in CY 2008 or later; payment based on OPPS relative payment weight |
| P3 | Office-based surgical procedure added in CY 2008 or later; payment based on MPFS nonfacility PE RVUs |
| J8 | Device-intensive procedure; paid at adjusted rate |
| N1 | Packaged service or item; no separate payment |
| K2 | Drugs and biologicals paid separately when integral to a covered surgical procedure |
| Z2 / Z3 | Radiology paid separately when integral to a covered surgical procedure |
Codes with indicators such as C5 (inpatient-only under OPPS) or E5 (not valid for Medicare) are not paid in an ASC, so scheduling should catch them before the case is booked. Commercial plans may cover a different list, so payer-specific coverage is checked as well.
Discounting, implants and discontinued cases
Under Medicare's multiple procedure rule, the MAC pays 100 percent of the highest-paying surgical procedure on the claim and 50 percent of the rate for each other covered procedure subject to discounting. A bilateral procedure is reported as two procedures, either on two lines or with two units on one line, and the 50 percent reduction applies. Line order and units therefore affect payment, and many commercial contracts follow their own discount schedule, so check your contract.
- Modifier 73: procedure stopped after the patient was prepared and taken to the operating room but before anesthesia; Medicare pays 50 percent of the rate
- Modifier 74: procedure stopped after anesthesia was induced; Medicare makes full payment
- Modifier FB: a specified device was furnished at no cost or with full credit
- Modifier FC: the ASC received a partial credit of 50 percent or more of the device cost
For commercial payers, implants are often carved out and paid at invoice cost or cost plus a set amount, which requires the invoice with the claim. We match implant logs and invoices to the contract terms so device payments are not left on the table.
Eligibility, authorization and documentation
Surgery cases are usually scheduled days or weeks ahead, which leaves time to confirm benefits, deductibles and the patient's estimated share. Our eligibility verification step confirms that the ASC is in network, not just the surgeon, and that the plan covers the procedure at an ASC rather than requiring a hospital outpatient setting.
Authorizations are matched to the CPT codes and site on the schedule. If the surgeon adds or changes a procedure, the approval is updated, ideally the same day. Documentation for the facility claim includes the signed operative report, anesthesia record, implant log and any pathology order, all tied to the date of service.
Common denials and how we prevent them
- Procedure not on the payer's ASC list: covered list and indicator checked at scheduling
- Authorization mismatch: approved codes compared with the operative report before the claim is sent
- Facility and professional codes disagree: both claims reviewed together
- Packaged items billed as separate lines: N1 items left off or reported per payer rules
- Implant carve-out underpaid or missing invoice: invoice attached and payment checked against the contract
- Wrong multiple procedure order or bilateral reporting: lines sequenced by expected payment
When denials do occur, our denial management team appeals with the operative report and approval, and short payments go to underpayment recovery for comparison with the contracted rate.
Credentialing for ambulatory surgery centers
An ASC participates in Medicare as a certified supplier, which requires meeting the Conditions for Coverage through a state survey or an accrediting organization with deeming authority, plus Medicare enrollment of the facility itself. State licensure, Medicaid enrollment and each commercial contract follow separate tracks, and surgeons who operate at the center keep their own enrollments.
Our credentialing and enrollment team tracks facility and physician applications through a nine-stage process and flags revalidation dates and ownership changes that need a filing.
How Fastora works with surgery centers
When you compare an ASC billing company, ask how it handles payment indicators, implant carve-outs and facility-to-surgeon code matching. Fastora's ASC billing services are delivered by certified billing and coding professionals working inside your existing practice management system, with a dedicated account contact and monthly reporting by payer and procedure.
Start with a free billing assessment of recent cases and remittances, and see how quotes are structured on our pricing page.
Surgery centers hosting eye and reconstructive procedures should review ophthalmology billing and plastic surgery billing for implant, bilateral and cosmetic-exclusion rules.
Ambulatory surgery center billing services
Ambulatory surgery center medical billing sits between physician and facility billing: the professional fee, the facility claim, and any implant or supply carve-outs each follow different rules and often different payers. An ambulatory surgery center billing company that works both sides keeps the two claims reconciled — the facility claim should never tell a different story than the operative report behind the professional fee. Our surgical billing services cover the full outpatient case: authorizations secured before the case, coding review after it, and follow-up on both claims until each pays. As an outpatient billing company, we also handle the cases that move between ASC and hospital outpatient settings, where the billing rules change with the place of service. Start with a free medical billing audit, or see how an ASC quote is built on our pricing page.