18.3 ASC versus Hospital Outpatient Department Billing
Key Takeaways
- Place of service 24 is the freestanding ASC; 22 is on-campus HOPD; 19 is off-campus outpatient hospital—do not swap them on the professional or ASC facility claim
- CMS-1834-FC (November 21, 2025) added 289 procedures to the CY 2026 ASC Covered Procedures List after revising CPL criteria, and added 271 codes that were removed from the IPO list
- ASC payment uses payment indicators in Addendum DD1 (A2, G2, J8, N1, K2, C5, and related values), not OPPS status indicators S/T/J1 from Addendum D1
- Device-intensive ASC procedures carry payment indicator J8; CMS defines device-intensive status from a device offset exceeding 30% of mean cost (since January 1, 2019), and modifier 73 removes 100% of the device offset before the discontinued-procedure reduction
- Hospital outpatient OR services typically use revenue code 0360 on the UB-04 13X claim; 0490 is the NUBC ambulatory-surgical-care family—Medicare freestanding ASC facility claims since January 1, 2008 use the CMS-1500 / 837P with POS 24 and do not carry UB-04 revenue codes
18.3 ASC versus Hospital Outpatient Department Billing
Quick Answer: Place of service (POS) 24 = freestanding ASC. POS 22 = on-campus HOPD. POS 19 = off-campus outpatient hospital. Medicare ASC facility claims use the CMS-1500 / 837P, not a hospital UB-04. ASC payment reads payment indicators (Addendum DD1), not OPPS status indicators (Addendum D1). For CY 2026, CMS (CMS-1834-FC) added 289 procedures to the ASC CPL after revising criteria and added 271 IPO-removed codes to that list.
AAPC's Taking the COC exam page states that surgery and modifiers covers procedures approved for outpatient hospital and ASC facilities. Candidates who can code a cataract but cannot tell HOPD from ASC miss that domain. This independent OpenExamPrep section is study support, not a CMS or AAPC billing manual.
Why the COC tests both businesses
The clinical CPT may be identical. The claim path is not. A hospital same-day surgery unit is a provider-based HOPD: institutional claim, type of bill 13X, revenue codes, OPPS Ambulatory Payment Classifications (APCs), Integrated Outpatient Code Editor (I/OCE) status indicators, packaging, and SI T multiple-procedure discounting. A Medicare-participating freestanding ASC is specialty 49: professional-format facility claim, POS 24, ASC fee schedule, ASC CPL, and payment indicators. MCPM Chapter 14 is the ASC claims chapter; Chapter 4 is the hospital OPPS companion; Chapter 26 is POS on the physician claim.
The ASC CPL "merely indicates procedures which are covered and paid for if performed in the ASC setting. It does not require the covered surgical procedures to be performed only in ASCs" (Chapter 14 §20.1). Site of service is a physician clinical decision. Coding still has to match the setting that actually treated the patient.
POS 24 versus 19 versus 22
| POS | CMS name | Facility claim that pairs with it |
|---|---|---|
| 22 | On Campus-Outpatient Hospital | Hospital UB-04 / 837I, TOB 13X; physician 1500 uses POS 22 |
| 19 | Off Campus-Outpatient Hospital | Same hospital 13X; physician 1500 uses POS 19 |
| 24 | Ambulatory Surgical Center | ASC facility 1500 / 837P and surgeon 1500, both POS 24 |
| 11 | Office | No hospital 13X and no ASC facility fee for that office service |
Do not put POS 24 on an on-campus hospital SDS case. Do not put POS 22 on a freestanding ASC. Do not use POS 11 for a registered HOPD patient to harvest the nonfacility physician fee (Chapter 26). Beginning January 1, 2008, Medicare ASCs do not use modifier SG; contractors assign type of service F to specialty 49 billed with POS 24. Historical TOB 83X is not how CMS processes ASC facility claims now.
CY 2026 ASC CPL: 289 plus 271
CMS-1834-FC (fact sheet, November 21, 2025) finalized a 2.6% ASC rate update for ASCs that meet quality reporting (same 3.3% market basket minus 0.7 productivity math used for OPPS) and extended the hospital market basket as the ASC update factor through CY 2026.
ASC CPL policy: CMS revised ASC CPL criteria, modified the general standard criteria, and eliminated five general exclusion criteria, moving them to nonbinding physician considerations for patient safety. As a result, CMS added 289 procedures to the ASC CPL. Additionally, CMS added 271 codes to the ASC CPL that were removed from the IPO list for CY 2026. Those 271 sit beside the IPO phase-out that starts with 285 mostly musculoskeletal procedures removed from IPO for CY 2026—related lists, different numbers. A code can leave IPO and still fail ASC CPL, or join ASC CPL and still have device-intensive or multiple-procedure rules.
Chapter 14 contractors deny ASC lines with payment indicators such as C5 (inpatient surgical procedure under OPPS; no ASC payment), U5 (surgical unlisted service excluded from ASC payment), and X5 (unsafe surgical procedure in ASC). Unlisted surgery is not a workaround to skip the CPL.
Payment indicators are not OPPS status indicators
OPPS status indicators (Addendum D1; CY 2026 includes S1 for unpackaged skin-substitute products) answer hospital questions: separately paid S versus multiple-procedure T, packaged N, comprehensive J1/J2, inpatient-only C. The I/OCE applies those letters to the 13X claim.
The ASC payment system assigns each covered surgical procedure and ancillary service a payment indicator published in Addendum DD1 and used on Addenda AA and BB. That alphabet is different. Common indicators COC candidates must not confuse with SIs:
| ASC payment indicator | Working meaning (Addendum DD1 / Chapter 14) | Not the same as |
|---|---|---|
| A2 / G2 | Covered surgical procedure paid at the ASC rate (legacy list versus later additions) | OPPS S or T |
| J8 | Device-intensive procedure; paid at an adjusted rate | OPPS device pass-through H |
| N1 | Packaged ASC item/service; no separate ASC payment | OPPS N, but a different editor and file |
| K2 | Separately payable drug/biological when integral to a covered surgical procedure | OPPS K or G |
| Z2 / Z3 | Certain radiology or other ancillary services payable when integral | OPPS radiology SI letters |
| C5 | Inpatient surgical procedure under OPPS; no ASC payment | Billing it with SI C on a 13X instead of denying it in the ASC |
| L6 | New technology IOL extra payment when assigned | Ordinary packaged lens |
Device-intensive. MCPM Chapter 4: beginning January 1, 2019, device-intensive procedures involve surgical implantation or insertion of an implantable device that has a CPT or HCPCS code (including single-use devices) and a device offset exceeding 30% of the procedure's mean cost. In the ASC those procedures carry J8. If the case is discontinued with modifier 73, contractors use the ASC fee-schedule field that already removed the device portion, then apply the 73 reduction (Chapter 14). That is the same policy idea as hospital 73 plus 100% device-offset removal, on a different file. Modifier 74 (after anesthesia or after start) still consumes facility resources; ASC 74 may still take multiple-procedure discounting, while ASC 52 and 73 do not take a further multiple-procedure haircut (Chapter 14 §40.5).
ASC multiple-procedure payment, when the procedure is discount-eligible, is 100% of the highest-paying procedure and 50% of the others—not I/OCE ranking of SI T lines. Applying hospital SI T logic to an ASC claim is the classic wrong alphabet.
Revenue codes 0490 versus 0360
National Uniform Billing Committee (NUBC) revenue 0360 is Operating Room Services—the usual hospital SDS/OR department on a 13X claim, often with 0361 for minor surgery when the chargemaster is built that way. Revenue 0490 is Ambulatory Surgical Care. Hospitals and some commercial ASC bills that still travel on a UB-04 may use 0490 for that department.
Medicare freestanding ASC facility claims do not use revenue codes. Since January 1, 2008 they are CMS-1500 / 837P with POS 24. Putting 0490 on a Medicare ASC 1500 is a category error. Putting 0360 on a freestanding ASC Medicare claim is the same error in the other direction. A hospital outpatient OR that is not a freestanding ASC still belongs on 13X with 0360 (or the hospital's mapped OR revenue), OPPS SIs, and POS 22 or 19 on the surgeon's claim.
COC items that mention 0490 are usually testing whether you know the NUBC family and that it is not the Medicare ASC 1500 path. Items that mention 0360 are testing hospital OR. Items that mention J8 versus T are testing payment indicator versus status indicator.
CMS also continued temporary separate payment for certain non-opioid pain treatments in both HOPD and ASC from 2025 through 2027; for CY 2026 CMS finalized five drugs and 11 devices as separately payable in both settings. That is an add-on policy, not a reason to ignore the CPL.
Facility scenario
Same CPT: extracapsular cataract with IOL. HOPD: 13X, revenue 0360, cataract HCPCS, IOL HCPCS, OPPS SI from Addendum B, physician POS 22. Freestanding Medicare ASC: ASC 1500 POS 24 with the cataract CPT only if it is on Addendum AA; read the payment indicator, not SI T; IOL ancillary follows Addendum BB (possible L6 if a new-technology IOL applies); surgeon 1500 also POS 24. Move a CY 2026 IPO-removed musculoskeletal case that is among the 271 added to the ASC CPL into an ASC only after Addendum AA says so—not because the hospital can now do it outpatient under the 285 IPO removals.
Sources
A surgeon operates in a Medicare-participating freestanding ASC. Which place-of-service pairing is correct?
What did CMS-1834-FC finalize for the CY 2026 ASC Covered Procedures List?
Which statement correctly contrasts ASC payment indicators, OPPS status indicators, and revenue codes 0360 versus 0490?