CMS finalized a 2.3% average CY2027 ASC update (3.2% market basket minus 0.9 percentage point), ASC conversion factor $57.721, 618 Covered Procedures List additions, and 637 inpatient-only removals. ASCA notes top-volume codes can pay less than in 2026, so coding accuracy protects margin.
| CY2027 figure | Number | What it means for coding ops |
|---|---|---|
| Average ASC payment update | 2.3% | 3.2% hospital market basket minus a 0.9 percentage point productivity adjustment |
| ASC conversion factor (ASCQR met) | $57.721 | Multiplier behind most ASC facility rates when quality reporting is met |
| HOPD (OPPS) conversion factor | $99.970 | Continues the ASC-to-HOPD rate gap even while inflation updates stay aligned |
| Codes added to the ASC Covered Procedures List | 618 | New eligibility checks before a code can be billed in the ASC setting |
| Procedures removed from the inpatient-only list | 637 | More cases may be clinically appropriate outside inpatient, with setting validation still required |
Figures above are from the CMS CY2027 OPPS/ASC final rule (CMS-1850-FC) and the CMS ASC regulations notice for CMS-1850-FC . Rate-mix context also appears in the ASCA final-rule summary dated 4 November 2026 .
What the CY2027 ASC final payment rule is
The CY2027 ASC final payment rule is CMS's annual update to how Medicare pays ambulatory surgical centers for covered facility services, issued with the hospital outpatient (OPPS) rule under the CMS ASC final-rule notice for calendar year 2027. It sets the ASC conversion factor, revises the ASC Covered Procedures List (CPL), continues the inpatient-only (IPO) list phase-out, and updates ASC Quality Reporting Program requirements.
It is a payment and coverage-list rule, not a coding-guideline rewrite. Coders still apply CPT, HCPCS, NCCI edits on ASC claims , and payer edits. What changes is which codes Medicare will pay in the ASC setting, how those codes are priced, and which setting assumptions still hold after IPO removals.
Why coding accuracy is now a margin control
A positive average update does not protect every line. ASCA reports that for 2027, all of the top 10 codes by volume will experience a decrease in reimbursement from 2026 rates. The association also notes that the 2.3% update is an average and that updates can vary significantly by code and specialty.
That mix matters for ASC medical coding teams. Underpayment on a high-volume line is not only a rate problem. It compounds when the claim carries the wrong payment indicator, packs a separately payable item into a packaged code, sequences multiple procedures incorrectly, or bills a newly CPL-eligible code without the supporting documentation the record needs. The habits that keep those lines clean are covered in coding accuracy for ASCs .
For ASCs , the operational risk on Monday is not "did CMS publish a table." It is whether the charge master, encoder edits, and coder checklist match the finalized CPL, Addendum payment indicators, and IPO removals before January claims go out.
What CMS finalized for CY2027
CMS states that it is increasing payment rates under the ASC payment system by 2.3 percent for ASCs that meet ASCQR requirements, based on a hospital market basket percentage increase of 3.2 percent reduced by a final productivity adjustment of 0.9 percentage point. In the same final rule, CMS is extending use of the hospital market basket as the ASC update factor for one additional year, through CY 2027, so ASC and HOPD inflation updates stay aligned for another year even though the conversion factors remain different ($57.721 ASC versus $99.970 OPPS).
On the covered list, CMS is continuing to expand the ASC CPL by adding 618 codes that were recommended by interested parties or were finalized for removal from the IPO list for CY 2027. CMS is also continuing to phase out the IPO list by removing 637 services across multiple clinical families for CY 2027.
ASCA's summary of the same final rule reports the same 2.3% effective update, the $57.721 ASC and $99.970 HOPD conversion factors, the 618 CPL additions, and the 637 IPO removals. ASCA also notes that CMS finalized removal of the Appropriate Follow-Up Interval for Normal Colonoscopy in Average Risk Patients measure (ASC-9) from the ASC Quality Reporting Program.
Code-level national rates live in the CMS ASC addenda files published with the rule, not in a trade-press roundup. Before any specialty impact claim, pull the code from Addendum AA or the related ASC addenda on the CMS ASC final-rule notice page. The CY2027 ASC addenda table of contents explains which file holds what: Addendum AA lists covered surgical procedures, Addendum DD1 defines payment indicators, and Addendum EE lists excluded procedures. For a plain-language overview of the major provisions, CMS also published a CY2027 OPPS and ASC final rule fact sheet .
The distinctions coding teams still get wrong
Average update versus code-level pay. The 2.3% figure is the productivity-adjusted market basket applied through the conversion factor path. Individual HCPCS lines can still fall when relative weights, packaging, or device offsets move. ASCA's top-10 volume observation is the practical warning: volume-weighted pain can rise even when the average update is positive.
CPL eligibility versus clinical appropriateness. A code on the ASC CPL means Medicare will pay the facility claim in the ASC setting when other coverage rules are met. It does not mean every patient is appropriate for ambulatory care. Setting decisions remain clinical. Coding confirms the code is payable in ASC and that the record supports the procedure performed.
IPO removal versus automatic ASC billing. Removing a procedure from the inpatient-only list expands where Medicare may pay outside inpatient. It does not auto-convert every historical inpatient case into a clean ASC claim. Coders still validate CPL status, payment indicator, and documentation for the setting billed.
Payment indicator versus CPT description. The CPT narrative tells you what was done. The ASC payment indicator tells you how Medicare prices it (separately payable, packaged, device-intensive, and related packaging rules). Indicator errors are a common path to ASC procedure bundling errors on multi-procedure days.
Inflation alignment versus rate parity. Extending the hospital market basket to ASC for CY2027 keeps the update methodology aligned with HOPD for another year. It does not close the conversion-factor gap between $57.721 and $99.970. For why that gap exists and how it shapes case placement, see ASC payment rates versus hospital outpatient rates .
Monday coding-ops checklist
Use this as the first-week control list after the final rule, not as a substitute for reading Addendum AA and your MAC guidance. It sits alongside the recurring ASC billing mistakes that tend to surface when edits lag a rule change.
- Refresh CPL eligibility. Diff your encoder and charge-master ASC flags against the finalized 618 additions. Flag any code your surgeons already schedule that newly joins the CPL.
- Re-check payment indicators. For every high-volume code and every newly added CPL code in your mix, confirm the CY2027 ASC payment indicator and packaging behavior before the first January claim.
- Re-sequence multiple-procedure logic. Where discounting applies, confirm primary versus secondary sequencing rules still match your scrubber and coder tip sheet.
- Validate IPO-to-outpatient setting moves. For codes among the 637 IPO removals that your surgeons may now schedule outside inpatient, require setting validation and documentation review before the first ASC claim.
- Update device and implant expectations. Device-intensive and packaged-device lines change economics even when the CPT code looks familiar. Route those charts through a second look until the new indicators are stable in production.
- Align prior authorization and payer overlays. Medicare CPL status does not rewrite commercial contracts. Sync auth lists and payer edits with the same code set your billers will use in January.
- Brief the OR and scheduling desks. New CPL codes fail upstream when the case is booked under an old inpatient habit. Give scheduling the short list of newly ASC-eligible codes in your service lines.
- Retire ASC-9 reporting assumptions. If your quality file still treats ASC-9 as active for ASCQR, update the measure inventory to match the finalized removal.
When documentation is thin on a newly ASC-eligible or newly outpatient-feasible case, stop and query. Do not "fix" setting from the rate table. For the documentation gaps to watch first, see common ASC operative report errors .
How MediCodio AI fits a technical read of the rule
Where centers want software support for that discipline across rising ASC volume, MediCodio AI keeps the work inside two lanes. Complete charts flow through AutoPilot for fully autonomous coding. Charts where the documentation is thin or contradictory stay in CoPilot, where certified coders review and finalize the output. For a broader view of how ASC teams use AI on coding ops without treating the model as the policy, see ASC medical coding AI automation .
What has not changed
CPT, ICD-10-CM, and CMS NCCI edits still govern code selection and edits. Physician clinical judgment still governs whether a given patient belongs in an ASC. Commercial and Medicare Advantage contracts can be stricter than the Medicare CPL. The ASC conversion factor still sits well below the OPPS conversion factor even while the inflation update methodology stays aligned for CY2027.
The final rule expands what can be paid in ASC and reprices the existing mix. It does not replace the coder's responsibility to match the claim to the record.
Frequently asked questions
What is the average ASC payment update for CY2027?
CMS finalized a 2.3% average ASC payment update for CY2027 for centers that meet ASC Quality Reporting requirements. That figure is the 3.2% hospital market basket percentage increase reduced by a 0.9 percentage point productivity adjustment. Individual codes can still move by more than 2.3% once relative weights and packaging are applied.
How many procedures were added to the ASC Covered Procedures List for 2027?
CMS finalized addition of 618 codes to the ASC Covered Procedures List for CY2027. The final rule describes those codes as ones recommended by interested parties or finalized for removal from the inpatient-only list for CY2027. ASCA's summary of the final rule reports the same 618-code expansion, including hernia codes ASCA had requested.
What happened to the inpatient-only list in CY2027?
CMS is continuing its IPO list phase-out by removing 637 services for CY2027 across multiple clinical families named in the final rule. Removal means Medicare may pay the service outside the inpatient setting when other rules are met. It does not by itself authorize every historical inpatient case as an ASC claim without CPL, indicator, and documentation checks.
Did ASC and HOPD inflation updates stay aligned?
Yes for CY2027. CMS extended use of the hospital market basket as the ASC payment system update factor for one additional year, through CY2027. ASC and HOPD therefore share the same 2.3% update math for that year, while the conversion factors remain different: $57.721 for qualifying ASCs and $99.970 under OPPS.
What should coding ops change on Monday?
Refresh CPL eligibility for the 618 additions, re-verify ASC payment indicators and packaging, re-test multiple-procedure sequencing, and add setting validation for IPO removals that may now appear on ASC schedules. Sync prior auth and commercial overlays, and update ASCQR measure inventory for the ASC-9 removal. Treat the CMS addenda as source of truth over secondary summaries.
If your ASC team is stress-testing CY2027 CPL adds, payment indicators, and sequencing against real operative notes, Book a Demo and run the workflow on your own charts and your own cases.
Related reading: ASC medical coding services · How MediCodio AI supports ASCs · ASC payment rates vs hospital outpatient rates · NCCI edits on ASC claims · Coding accuracy for ASCs · ASC procedure bundling errors · Common ASC billing mistakes · ASC billing compliance in 2025
Sources
- CMS CY2027 OPPS/ASC final rule with comment period (CMS-1850-FC), public inspection PDF
- CMS ASC regulations and notices: CMS-1850-FC
- ASCA, 2027 Final Payment Rule summary (2026-11-04)
- CMS fact sheet: CY2027 OPPS and ASC final rule
- CMS CY2027 ASC addenda table of contents (PDF)
- CMS National Correct Coding Initiative (NCCI) for Medicare