What changed

The grandfather clause just got narrower

Since Section 603 of the Bipartisan Budget Act of 2015 took effect, off-campus provider-based departments have lived in two worlds. Excepted departments, those billing under OPPS before the statutory cutoff, kept the full hospital outpatient rate and append modifier PO. Non-excepted departments bill with modifier PN and already receive a reduced, site-neutral rate. CMS previously applied a site-neutral policy to clinic visits at excepted sites; CMS-1850-P now proposes doing the same for certain imaging-without-contrast services, at 40% of the OPPS rate.

The matrix below shows exactly who is touched and who is not.

Comparison matrix

Imaging without contrast: payment by site of service under CMS-1850-P

The math on one dollar

What 40% of OPPS means on an affected line

Two details matter for modeling. First, the cut is service-scoped, not site-scoped: an excepted department keeps full OPPS on everything outside the affected imaging-without-contrast set, so the revenue exposure is exactly the volume you bill on those lines with modifier PO. Second, this is a proposed rule. The 40% figure, the scope of affected imaging services, and the enrollment requirements can all move between now and the final rule, which is precisely why the comment window matters.

Timeline

Dates that govern your response

The second policy inside the rule

New enrollment requirements for off-campus HOPDs

The payment cut is getting the headlines, but CMS-1850-P also proposes new enrollment requirements for off-campus hospital outpatient departments. For health systems that have added, relocated, or expanded off-campus sites over the years, this is a data-integrity problem before it is a payment problem: CMS will be looking at how each off-campus location is enrolled, and departments whose provider-based status, addresses, or practice locations are stale in enrollment records create avoidable risk. An enrollment file that does not match how you actually bill PO and PN today is the wrong place to be standing when a site-specific payment policy arrives.

Operator playbook

Six moves before the comment window closes

1. Pull PO/PN modifier volumes by site. This is the first operational step. Extract 12 months of hospital outpatient claims, split by modifier PO versus PN and by department location, so you know exactly which imaging volume sits in excepted off-campus sites.
2. Isolate imaging-without-contrast lines. Within the PO population, flag the non-contrast imaging services. That subset times the roughly 60% reduction is your gross exposure under the proposal as written.
3. Model CY 2027 revenue at 40% of OPPS. Re-price the affected lines at 40% of the current OPPS rate and roll the delta up by site, service line, and payer, since Medicare Advantage plans that shadow OPPS methodologies may follow.
4. Audit off-campus enrollment records now. Reconcile every off-campus department's enrollment data, addresses, and provider-based attestations against how claims actually go out the door, ahead of the proposed enrollment requirements.
5. File a comment by August 31, 2026. CMS reads specificity. Site-level volume, access, and margin data on affected imaging services is far more persuasive than a form letter, and the window closes August 31, 2026.
6. Scenario-plan site strategy. If the policy finalizes, test whether affected imaging volume is better served in current locations at the reduced rate, consolidated on campus, or restructured, with compliance counsel in the room before any move.