Medical specialties
Primary and family care
Surgical and procedural
Dental, DME and labs
Revenue cycle · one rate
Front end · before the visit
Patients, insight and growth
Clinical documentation
Revenue operations
Voice automation
ASC billing services · Surgery · Anesthesia
PhysiAssist runs billing for ambulatory surgery centers and the surgeons who operate in them: facility claims, professional fees, anesthesia and implants, one case at a time. We check every payment against your contract, so multiple-procedure cuts, unpaid implant carve-outs and underpaid cases get caught and recovered.
Multiple-procedure payment
Try itPaid on this claim
$0Left on the table
$0Sample contract rates; 100% for line 1, 50% after
The basics
ASC billing is the revenue cycle of an ambulatory surgery center: the facility fee for the room, staff and supplies, billed separately from the surgeon's professional fee and the anesthesia claim, plus implants and high-cost supplies under each payer's contract. Most lost ASC revenue hides in underpayments, not denials, so every payment has to be checked against the contract.
CMS-1500 for Medicare, UB-04 with revenue codes where the contract asks, case rates and the ASC covered procedures list.
Global periods, modifiers 58, 78 and 79, assistants at surgery and the visits around each case.
Base and time units, MD and CRNA modifiers, monitored anesthesia care and medical direction.
Invoices matched to claims, carve-outs billed at contract terms, pass-through devices coded.
Surgical specialties
Arthroscopy, total joints on the ASC list, spine decompression, implants and bilateral rules.
Screening that turns diagnostic (PT and 33 modifiers), polyp removal and EGD with biopsy.
Epidurals, facet injections, radiofrequency ablation and stimulator trials with their authorizations.
Cataract with premium lens billing, functional vs cosmetic plastics, hernia and general surgery.
What we check
| Codes | What they cover | What we check |
|---|---|---|
| CMS-1500 · UB-04 · Rev 0360 · 0490 | Facility claim form and revenue codes | Which form and revenue codes each payer's contract requires for the facility fee |
| Multiple-procedure rule | Second and later procedures paid at a reduced rate | Highest-paying procedure first, and the payment checked against the contract percentages |
| Modifier 50 · RT/LT | Bilateral procedures | The payer's bilateral method: one line with 50, or two lines with RT and LT |
| Modifier 73 · 74 | Procedure stopped before or after anesthesia | The right modifier so a cancelled case still pays what the rules allow |
| Rev 0278 · L8699 · C-codes | Implants and pass-through devices | Invoice on file, carve-out terms applied and the device code each payer accepts |
| PT · 33 | Screening colonoscopy that becomes diagnostic | The modifier each payer needs so the patient keeps screening benefits |
| AA · QK · QX · QZ · QS | Anesthesia provider and MAC modifiers | Medical direction, CRNA billing and monitored anesthesia care matched to the record |
| 58 · 78 · 79 | Procedures inside a global period | Staged, return-to-OR or unrelated procedures billed so the global period does not swallow them |
Free ASC underpayment audit
Send us recent cases and your fee schedules. We compare every payment with what the contract says and send a written report you keep, whether or not you work with us.
Cases reviewed
180Paid under contract
17Dollar impact
$21,400What the report covers
Result
We took over the full revenue cycle for an orthopedic group in California in 2025. Within 45 days, days in AR fell from 59 to 35.
Days in AR, before
59
Within 45 days
35
The systems we work in every day
We log in to your system; nothing about it changes for your team.
Claims, rejections and remittances worked through your clearinghouse.
Submissions, status checks and renewals in each payer's own portal.
Pricing
One rate of 2.8% to 5% of net collections, quoted in writing before you sign. Where you land depends on monthly collections, specialty mix, the scope of services, and your AR backlog and payer mix.
The rate covers medical coding, claim submission, payment posting, denials and AR follow-up. Front desk services, prior authorization, the reporting dashboard, patient statements, credentialing and digital marketing are quoted separately.
See full pricing and estimate your rate →ASC billing services manage the revenue cycle of an ambulatory surgery center: facility claims, surgeon professional fees, anesthesia, implant and supply billing, multiple-procedure and bilateral rules, payer contract checks, payment posting, denials and AR follow-up.
An ASC bills a facility fee for the room, staff and supplies, separate from the surgeon's professional fee and the anesthesia claim. Medicare takes ASC facility claims on the CMS-1500 (837P), while many commercial payers want the UB-04 (837I) with revenue codes, so the form depends on the payer contract.
When several procedures are done in one session, payers usually pay the highest-paying procedure in full and reduce the others, commonly to 50%. Medicare ranks procedures itself; under many commercial contracts the cut follows the line order on the claim, so listing the highest-paying procedure first matters.
Implants are billed according to the payer contract: some pay them inside the case rate, others as a carve-out at invoice cost plus a percentage. We match each implant invoice to the claim, use the right HCPCS or revenue code (for example 0278), and check the carve-out was paid.
Yes. We bill anesthesia with base units plus time units, physician and CRNA modifiers such as AA, QK, QX and QZ, and monitored anesthesia care with QS, so the anesthesia claim matches the surgery claim.
Orthopedics and spine, GI and endoscopy, pain management, ophthalmology, plastic surgery and general surgery, for both the facility and the surgeons.
PhysiAssist charges 2.8% to 5% of net collections for coding, claims, posting, denials and AR, quoted in writing before you sign. Industry guides commonly cite 8% to 12% for surgical billing.
We take recent cases, compare what each payer paid with your contracted rates, and send a written report: underpaid cases by payer, multiple-procedure and implant errors, denials by root cause and the dollar value of each.
A free ASC underpayment audit: every recent case checked against your contract, with a written report you keep.