POS 51 in Medical Billing: The Inpatient Psychiatric Code That Decides Your Facility Rate and the 190-Day Clock

POS 51 in medical billing is the Place of Service code for an Inpatient Psychiatric Facility. You report it in Box 24B of the CMS-1500 professional claim, and it pays at the Medicare facility rate.

This guide covers place of service 51 from the claim field to the remittance. You’ll get the registered inpatient rule, the split from POS 21, the FY 2027 IPF PPS rates that start October 1, 2026, the CPT pairings, the denial codes, and the 190-day limit that catches freestanding psychiatric hospitals off guard.

What Does POS 51 Mean in Medical Billing?

The Official CMS Definition of Place of Service 51

CMS defines POS 51 as a facility that provides inpatient psychiatric services for the diagnosis and treatment of mental illness on a 24-hour basis, by or under the supervision of a physician. Three clauses sit inside that sentence, and each one excludes a different setting.

The 24-hour basis clause rules out day programs. Physician supervision rules out residential settings that run without a physician directing care. Diagnosis and treatment of mental illness rules out facilities that treat substance use alone. Check your setting against all three before you code the line, per the CMS Place of Service Code Set.

Where POS 51 Goes on the CMS-1500 and the 837P

Place of service 51 belongs in Box 24B of the CMS-1500. On the 837P electronic transaction it maps to Loop 2400, data element SV105. POS 51 in medical billing sits at the service line level, not the claim level.

That line-level placement matters more than most billers expect. One claim covering two settings on the same date can carry two different POS codes on two different lines. Medicare treats POS as a required field, and a missing or invalid entry returns the service as unprocessable instead of denied.

Why POS 51 Never Appears on a UB-04

Institutional claims carry no place of service field. The UB-04 and its electronic counterpart, the 837I, don’t carry an equivalent of Box 24B. POS codes live on professional claims only.

Inside a psychiatric hospital, that split runs every day. The facility bills room, board, and nursing on the UB-04 under a psychiatric type of bill. On the professional side, the attending psychiatrist bills the same admission on the CMS-1500 with POS 51.

Those two claims also pay from two different systems. The facility side runs through the IPF Prospective Payment System under Part A, and POS 51 in medical billing governs the professional side, which pays under the Medicare Physician Fee Schedule under Part B. Neither one adjusts the other.

What Counts as an Inpatient Psychiatric Facility Under Medicare?

Medicare recognizes two types of inpatient psychiatric facility: freestanding psychiatric hospitals and distinct-part psychiatric units inside acute care or critical access hospitals. Both report POS 51 on professional claims. The facility type doesn’t change the code, but it changes almost everything behind it, including how psychiatric hospital revenue cycle teams handle coverage limits.

Freestanding Psychiatric Hospitals

A freestanding psychiatric hospital holds a license for psychiatric care and nothing else. These facilities follow the Special Conditions of Participation at 42 CFR 482.60 through 482.62.

In operating terms, that means a standalone license, a standalone CMS Certification Number, and a standalone cost report. Nothing routes through a parent hospital, because there isn’t one.

Distinct-Part Psychiatric Units Inside Acute Care Hospitals

A distinct-part psychiatric unit sits inside a general hospital and operates as a separate unit. It meets the standard hospital Conditions of Participation at 42 CFR 482 plus the additional requirements at 42 CFR 412.27. CMS sets out the facility criteria at 42 CFR Part 412 Subpart N.

The unit shares the parent hospital’s CCN with a unit identifier and carries its own bed count. It also maintains separate medical records and separate staffing from the rest of the hospital.

The Freestanding Test That Decides Which One You Are

A separate building on a hospital campus counts as freestanding unless it’s integrated with the hospital or operates as a department of it. Proximity doesn’t settle the question. Integration does.

Run that test before you assume your psychiatric building is a hospital unit. The distinction reads as paperwork until a patient hits a coverage limit that applies to one setting and not the other, which is where Section 8 of this guide picks up.

When Should You Use POS 51 on a Claim?

The Registered Inpatient Rule Most Billing Teams Get Backwards

Place of service follows the patient’s registration status, not the physical location of the encounter. CMS instructs that when you furnish services to a registered inpatient, you report an inpatient POS code regardless of where the face-to-face encounter happened.

Take the case that trips up hospital psychiatry teams. Nursing staff move a registered IPF inpatient to an outpatient imaging suite for a consult. The consulting physician still bills POS 51, because the patient’s registration status didn’t change when the gurney moved. See the Medicare Claims Processing Manual Chapter 26 for the underlying instruction.

Most billing guides describe pos 51 as the code for where the service happened. Teams that code from that framing put the wrong setting on the line. At charge entry, your biller needs to answer one question: what was this patient registered as on the date of service?

Services That Qualify for Place of Service 51

Why CMS Says May Use and Not Must Use

CMS manual language sets POS 21 as the minimum inpatient POS needed to trigger facility payment, and says the practitioner may report the more specific inpatient code when aware of the exact setting. That’s permissive language. Plenty of guides state that POS 51 in medical billing is required as an absolute, and the manual doesn’t say that.

Those two rules conflict inside a psychiatric setting, and most billing guides skip the conflict. CMS defines POS 21 as a facility other than psychiatric, which sits against an instruction naming POS 21 as the inpatient minimum.

The workable reading is this. The manual language sets a payment-trigger floor, while the code definition governs correct setting selection, which makes the specific code the defensible choice. If your organization plans to write a hard internal policy, confirm it with your Medicare Administrative Contractor first. Payer instruction varies, and POS 21 inpatient hospital code rules differ from psychiatric rules in ways that matter at the claim line.

POS 51 vs POS 21: The Mistake That Costs Psychiatric Units the Most

Why CMS Excludes Psychiatric Facilities From POS 21 by Definition

CMS defines POS 21 as a facility, other than psychiatric, that provides diagnostic, therapeutic, and rehabilitation services to admitted patients. Read the qualifier again: other than psychiatric. Most billing teams work from the short code label instead of the full definition, and the exclusion sits in that clause.

CMS built the exclusion into the code description itself. The two codes aren’t overlapping options you pick between on judgment. They exclude each other, and the definition settles which one applies.

The Decision Table for Hospital-Based Psychiatry

That last row is the one hospital psychiatry teams get wrong week after week. A patient boarding on a medical floor while the team hunts for a psychiatric bed isn’t an IPF inpatient yet. The consulting psychiatrist bills POS 21 until the transfer completes. Compare the full rule set for when POS 21 applies instead.

Observation status is the second place teams slip. A patient can sit in a hospital bed overnight with a psychiatric presentation and still hold outpatient status, which puts the encounter under emergency room place of service rules rather than inpatient ones.

What Happens When You Bill POS 21 for a Psych Unit Patient

A POS that doesn’t match the facility’s Medicare enrollment record produces a place-of-service inconsistency denial. You lose that claim until someone corrects the line and resubmits, which is the most common way POS 51 in medical billing goes wrong at the claim level.

The larger exposure is the pattern, not the single claim. Payer analytics and Recovery Audit Contractors both flag systematic POS misalignment, because a repeating mismatch between enrollment data and billed setting reads as a control failure rather than a typo.

How POS 51 Compares to the Other Behavioral Health Place of Service Codes

The Full Behavioral Health POS Comparison Table

Seven place of service codes cover behavioral health settings, and POS 51 in medical billing is the only one of them built for acute inpatient care. Picking between them comes down to two questions: does the patient stay overnight, and does a physician supervise the care?

Use the CMS names exactly as published. POS 58 is the Non-residential Opioid Treatment Facility, and several POS tables in wide circulation online still label it as a mental health facility. Billing from a mislabeled reference puts the wrong setting on the claim. The same discipline applies across the wider code set, including POS 50 federally qualified health center reporting.

POS 51 vs POS 52: Overnight Admission Is the Dividing Line

POS 52 covers partial hospitalization, a day program delivering therapy intensity above standard outpatient without a 24-hour stay. The operating tell is simple: if the patient goes home at night, the claim isn’t place of service 51, no matter how intensive the daily schedule looks.

POS 51 vs POS 55 and POS 56: Acute Care vs Residential

POS 55 covers residential substance abuse treatment for live-in residents who don’t need acute medical care. POS 56 covers a psychiatric residential treatment center providing 24-hour therapeutically planned group living, most often for children and adolescents.

Acuity and physician supervision separate these from POS 51, and duration has no bearing on it. A residential facility can house a patient for six months without meeting the threshold that pos 51 describes.

How POS 51 Affects Reimbursement in 2026 and 2027

Why POS 51 Pays the Facility Rate and What That Costs You

Place of service 51 is a facility setting under the Medicare Physician Fee Schedule. The professional claim pays the facility rate, which runs below the non-facility rate because Medicare reimburses practice expense and overhead to the institution instead of bundling it into the physician payment.

Compare that against the settings where the practice carries its own overhead. A physician billing from an office or a home visit collects the higher column, which is why non-facility rate settings pay more for identical physician work. Read the CMS Inpatient Psychiatric Facility PPS page for the facility side of the same admission.

The CY 2026 Physician Fee Schedule Change That Cut Facility Payments

CMS published the CY 2026 Physician Fee Schedule final rule, CMS-1832-F, on November 5, 2025, effective January 1, 2026. That rule changed how indirect practice expense RVUs get allocated by site of service.

Under that rule, CMS cut the portion of indirect PE RVUs tied to work RVUs in facility settings to half the amount used for non-facility services, reasoning that allocating indirect costs at the same rate in both settings no longer reflects contemporary practice. Published impact analyses put the facility RVU effect near negative 7%, with non-facility up about 7%. CMS also finalized a 2.5% efficiency adjustment to work RVUs for most non-time-based services. See the CMS CY 2026 Physician Fee Schedule fact sheet and the CMS-1832-F final rule record.

Translate that into your psychiatric claims. POS 51 in medical billing is a facility code, so every professional claim you bill under it in 2026 carries a lower practice expense allocation than identical work in a non-facility setting. That gap got wider in 2026, and it didn’t move in your favor. The same shift pushed payment toward settings like an independent clinic POS 49.

FY 2027 IPF PPS Rates Effective October 1, 2026

CMS issued the FY 2027 IPF PPS final rule on July 29, 2026 and published it on July 31, 2026. The rates below apply to discharges beginning October 1, 2026.

CMS also finalized a cap limiting an IPF’s outlier payment to 20% of its total annual IPF PPS payments, effective October 1, 2028, with an exception for facilities under 50 stays per year. Verify the figures against the Federal Register FY 2027 IPF PPS final rule before you update your rate tables.

How the Professional Claim and the Facility Claim Get Paid Separately

Two payment systems run against one admission. The professional claim carries POS 51 and pays under the Medicare Physician Fee Schedule at the facility rate. Its institutional counterpart carries no POS code at all and pays under IPF PPS at the per diem. Two forms and two rate tables settle against the same patient.

The 190-Day Lifetime Limit That Only Applies to Freestanding Psychiatric Hospitals

What the 190-Day Limit Covers and What It Does Not

Medicare Part A covers a lifetime maximum of 190 days of inpatient psychiatric hospital care in a freestanding psychiatric hospital. Once a beneficiary exhausts those days, Part A pays nothing further for that setting for the rest of their life.

The statute sits at Section 1812(b)(3) of the Social Security Act, codified at 42 U.S.C. 1395d(b)(3) and implemented at 42 CFR 409.62. Teams handling POS 51 in medical billing should read it as a lifetime counter rather than an annual one. It doesn’t reset at the start of a benefit period, and it doesn’t reset at the start of a year. Confirm current coverage detail through Medicare inpatient mental health coverage.

Why Distinct-Part Psychiatric Units Are Exempt

The 190-day limit applies to freestanding psychiatric hospitals. It doesn’t apply to a Medicare-certified distinct-part psychiatric unit of an acute care or critical access hospital.

The same admission and the same length of stay run capped in one setting and uncapped in the other. That freestanding test from earlier in this guide looked like licensing paperwork. Use it to find out whether a lifetime clock starts on your patient.

Lifetime Reserve Days Do Not Extend the 190-Day Cap

A beneficiary can’t draw the 60 lifetime reserve days to stretch a stay at a freestanding IPF. Only the 190 days are available in that setting. Your MAC can confirm the application against a specific beneficiary record, and Noridian freestanding psychiatric lifetime limit guidance sets out the operating rule.

How to Track Remaining Days Before Admission

Remaining psychiatric days show up in the Medicare eligibility transaction, so your access team can check them before the patient reaches the floor. A freestanding IPF that admits a beneficiary with exhausted days has no Part A payment source for the stay.

Build that check into pre-admission alongside eligibility and authorization. Finding out on the remittance means the care already happened, the bed already turned, and there’s no appeal for a benefit that ran out.

Which CPT Codes Are Billed With POS 51?

Psychiatric Diagnostic Evaluation Codes 90791 and 90792

CPT 90791 is the psychiatric diagnostic evaluation without medical services. Psychologists, clinical social workers, and counselors report it at intake. Its counterpart, 90792, covers the evaluation with medical services, and psychiatrists and psychiatric nurse practitioners who prescribe or order diagnostic testing report that one.

The medical component separates them, not the setting. Both codes work in an inpatient psychiatric facility, and the choice turns on what the clinician did and what they’re licensed to do. The AMA behavioral health coding guide carries the current descriptors.

Can You Bill 99221 Through 99239 With POS 51?

Yes, inpatient E/M codes 99221 through 99239 report with POS 51, though conflicting guidance circulates and your payer may restrict it.

Coders run into two competing claims online. One instructor position shared across coding forums holds that 99221 through 99239 belong only with POS 21 or 22. A separate practitioner thread reports a payer stating that only 90791 and 90792 pay with POS 51. Both of those discussions rank in search results, which is how the confusion spreads.

The governing logic resolves it. Since the 2023 CPT revisions merged observation and inpatient care into one series, 99221 through 99239 describe hospital inpatient or observation care as a service. POS 51 describes the setting on the professional claim. The two answer different questions, so they don’t compete. The subsequent care codes carry the daily volume, and CPT 99232 subsequent hospital care is the one most psychiatric units bill.

Confirm any payer-specific restriction with your MAC or the plan before you build a rule around it. One payer’s policy isn’t a universal standard for POS 51 in medical billing, and ChampVA, Medicaid MCOs, and commercial plans each publish their own edits.

Psychotherapy Add-On Codes When E/M Is Performed the Same Day

A psychiatrist who delivers both an E/M service and psychotherapy on the same date bills the E/M code plus the psychotherapy add-on. Don’t bill the standalone psychotherapy code alongside E/M.

Add-on +90785 for interactive complexity applies when documented complicating factors are present during the session. The time thresholds match the standalone psychotherapy codes, so the CPT 90834 documentation rules apply to +90836, and the 60-minute psychotherapy billing thresholds apply to +90838.

The Provider Credential Rule That Decides Which Code You Can Use

A non-prescribing clinician can’t bill a code that requires a prescriber, and the setting doesn’t change that. A licensed clinical social worker who reports 90792 draws a denial on provider taxonomy.

Watch this one, because it masquerades as something else. Teams read the denial, see an inpatient psychiatric claim, and open a place-of-service investigation when the actual failure sits in the credential file. Check the rendering provider’s taxonomy against the code before you touch the POS.

What Documentation Do POS 51 Claims Require?

Physician Certification and the Day 12 Recertification Deadline

Medicare Part A pays for inpatient psychiatric services only when a physician certifies and recertifies that the care is needed. The certification rules sit at 42 CFR 424.14.

The certification has to state that inpatient psychiatric services were required for treatment that could reasonably be expected to improve the patient’s condition, or for diagnostic study, and that the services met the admission order requirements at 42 CFR 412.3.

The first recertification is due by day 12 of the stay. After that, the utilization review committee sets the schedule, and recertifications can’t fall more than 30 days apart. Put day 12 on the unit calendar, because it’s the date that catches teams mid-admission. Coverage criteria sit in LCD L34183 Psychiatric Inpatient Hospitalization.

What the Psychiatric Admission Note Must Contain

Why Patient Stable, Continue Plan Fails an Audit

Progress notes have to show active treatment on each billed day. Active treatment means documented therapy, medication management, behavioral intervention, or other care that needs the inpatient level to deliver.

Auditors read repetition as a signal. A chart carrying the same two-line note across six days suggests custodial care, and Medicare doesn’t cover custodial care under the psychiatric benefit. Reviewers working POS 51 in medical billing audits look for that pattern first, because it’s the fastest way to separate an active stay from a warehoused one.

Why POS 51 Claims Get Denied and How to Fix Each One

Place of Service Mismatch Denials: CARC CO-5 and CO-58

CARC CO-5 tells you the procedure code or type of bill doesn’t fit the place of service reported. Its neighbor, CO-58, tells you the payer decided the treatment happened in an inappropriate or invalid setting. Both land on POS 51 claims for different reasons.

Work them in the same sequence. Verify the patient’s registration status on the date of service, confirm the facility’s Medicare certification as an IPF, correct the POS on the affected service line, then resubmit as a corrected claim rather than a new one. A new claim on a corrected line creates a duplicate denial on top of the original.

Facility NPI and Taxonomy Mismatch in Box 32 and Box 24J

The facility NPI in Box 32 has to match the IPF where the service happened. The rendering provider NPI in Box 24J has to match a practitioner credentialed for that service with that payer.

A credential failure looks like a place-of-service failure on the remittance. Both surface as adjudication failures on an inpatient psychiatric claim, so teams open a POS investigation and find nothing wrong with the code. Pull the enrollment record before you touch Box 24B, and route the fix through provider enrollment and credentialing when the taxonomy is the gap.

Missing Prior Authorization on Medicare Advantage and Commercial Admissions

Commercial plans and Medicare Advantage plans often require prior authorization or concurrent review for psychiatric admissions. Missing authorization is a leading cause of full denial on inpatient psychiatric claims.

Separate the two failure modes, because each one appeals on different grounds. A missing authorization is one problem. Authorization expiring mid-stay while the patient remains admitted is another, and it produces a partial denial covering the unauthorized days. The CO-197 authorization denial path handles both, but the documentation you attach differs.

Telehealth Billed as POS 51

Telehealth services use POS 02 or POS 10 with the appropriate modifier, not POS 51. That rule holds for routine telepsychiatry delivered to a patient at home or at an originating site.

The harder question comes up inside the hospital. A psychiatrist delivering a telehealth encounter to a patient who is a registered IPF inpatient sits at the intersection of two rule sets, because registration status governs the inpatient POS determination while the telehealth rules govern the modifier. Confirm that combination with the payer before you bill it. Telehealth statutory authority has shifted several times and carries date-sensitive exceptions, so verify current status as of your date of service. This paragraph reflects guidance available in September 2026.

The Denial Code Reference Table for Psychiatric Claims

Work these by root cause instead of batching resubmissions. A CO-16 corrects and reprocesses without an appeal, while a CO-50 needs clinical documentation and a written argument. That split is where most POS 51 in medical billing recovery work gets won or lost. One O Seven RCM’s place-of-service denial recovery team starts from the CARC on the remittance and routes each denial down its own path.

The Pre-Submission Checklist for POS 51 Claims

Verify Before the Claim Goes Out

Six checks catch most POS 51 in medical billing failures before a payer sees the claim. Run them in order at charge entry.

1. Confirm the facility holds Medicare certification as an IPF or a qualifying distinct-part psychiatric unit.
2. Verify the patient’s registration status and signed admission order for the date of service.
3. Check remaining psychiatric days if the facility is freestanding.
4. Confirm authorization is active and unexpired across the full billed span through prior authorization verification.
5. Match the facility NPI in Box 32 and the rendering provider taxonomy to the billed service.
6. Run payer-specific edits and NCCI checks before submission.

Reconcile the CMS-1500 Against the UB-04 Monthly

Dates of service, diagnoses, and authorization numbers should match across the professional CMS-1500 and the institutional UB-04 for the same admission. A divergence means one of the two claims is wrong.

That divergence stays invisible until an auditor finds it, which is usually months after the window to correct anything has closed. Run the reconciliation as a standing monthly control rather than a task someone picks up when there’s time.

POS 51 Is Not Modifier 51, Condition Code 51, or Discharge Status 51

Four different codes in medical billing carry the number 51, and they sit on different forms for different purposes. Search engines conflate them, which is how a coder looking up place of service 51 ends up reading about multiple procedure reductions.

POS 51 vs Modifier 51

Modifier 51 is a CPT modifier showing that one provider performed multiple procedures in the same session, and it triggers multiple procedure payment reduction. Location has nothing to do with it.

Medicare contractors don’t require modifier 51 in most cases, because the claims processing system applies the reduction logic on its own. Appending it by hand can produce processing errors rather than preventing them.

POS 51 vs Condition Code 51

Condition code 51 is an institutional claim code reported on the UB-04. It has no relationship to place of service. It sits on a different form, and it serves a different purpose.

POS 51 vs Patient Discharge Status 51

Patient discharge status 51 is a discharge disposition code on the institutional claim. It describes where the patient went at the end of the stay, not where the service happened.

Keep this table near your claim scrubber rules. POS 51 in medical billing gets flagged by teams who pulled the wrong 51 from a reference sheet, and the correction costs more than the lookup would have.

POS 51 in Medical Billing: Frequently Asked Questions

What is POS 51 in medical billing?

POS 51 is the Place of Service code for an Inpatient Psychiatric Facility. You report it in Box 24B of the CMS-1500 and in Loop 2400, data element SV105, on the 837P. CMS defines the setting as a facility providing inpatient psychiatric services on a 24-hour basis under physician supervision.

Is POS 51 inpatient or outpatient?

POS 51 is inpatient. The patient has to be formally admitted and registered at a Medicare-certified inpatient psychiatric facility. A patient in observation status holds outpatient status regardless of how many nights they spend in the building, and that encounter belongs under a different code.

Is POS 51 a facility or non-facility place of service?

POS 51 is a facility place of service under the Medicare Physician Fee Schedule. The professional claim pays the facility rate, which sits below the non-facility rate because the institution bills its overhead separately on the UB-04 under IPF PPS.

Where does POS 51 go on the claim form?

Place of service 51 goes in Box 24B of the CMS-1500, entered at the service line level rather than the claim level. On the 837P it maps to Loop 2400, data element SV105. One claim covering two settings on the same date can carry two different POS codes.

What is the difference between POS 51 and POS 21?

CMS defines POS 21 as a facility other than psychiatric, so the two codes exclude each other by definition. Use POS 51 for a patient registered at a psychiatric hospital or an excluded psychiatric unit. Use POS 21 for a patient admitted to acute care, including a psychiatry consult on a medical floor.

What is the difference between POS 51 and POS 52?

The overnight admission separates them. POS 51 covers inpatient psychiatric care requiring a 24-hour stay. POS 52 covers partial hospitalization, a structured day program more intensive than standard outpatient care where the patient returns home at night.

Which CPT codes can be billed with POS 51?

Inpatient E/M codes 99221 through 99239, psychiatric diagnostic evaluations 90791 and 90792, and psychotherapy add-ons +90833, +90836, and +90838 when performed with an E/M service. Add-on +90785 applies for documented interactive complexity. Confirm payer-specific restrictions before building a standing rule.

Can POS 51 be used for telehealth?

No. Telehealth uses POS 02 or POS 10 with the appropriate modifier. The exception worth confirming with your payer is a telehealth encounter delivered to a patient already registered as an IPF inpatient, where registration status and telehealth rules intersect. Verify current telehealth authority as of your date of service.

Does the 190-day lifetime limit apply to all psychiatric facilities?

No. Medicare’s 190-day lifetime limit on inpatient psychiatric care applies to freestanding psychiatric hospitals only. It doesn’t apply to a Medicare-certified distinct-part psychiatric unit of an acute care or critical access hospital. Lifetime reserve days can’t extend the 190 days at a freestanding facility.

Why was my POS 51 claim denied?

The most common causes are a registration status mismatch producing CARC CO-5 or CO-58, a facility or rendering provider NPI that doesn’t match the enrollment record, missing or expired prior authorization producing CO-197, and missing active treatment documentation producing CO-50. Start with the CARC on the remittance.

Is POS 51 the same as modifier 51?

No. POS 51 identifies an inpatient psychiatric facility on a professional claim. Modifier 51 signals that one provider performed multiple procedures in a single session and triggers a payment reduction. They share a number and nothing else.

Does POS 51 appear on a UB-04?

No. The UB-04 and the 837I carry no place of service field. Institutional claims identify the setting through the type of bill and revenue codes instead. POS 51 appears on professional claims only, which is why the psychiatrist and the facility file two separate claims for one admission.

POS 51 Key Takeaways

• POS 51 is the CMS place of service code for an Inpatient Psychiatric Facility, reported in Box 24B of the CMS-1500 and Loop 2400 SV105 on the 837P.
• Registration status governs the code, not the room where the encounter happened. A registered IPF inpatient seen elsewhere in the building still generates a POS 51 professional claim.
• CMS defines POS 21 as a facility other than psychiatric, which makes POS 21 and POS 51 exclusive of each other by definition.
• POS 51 pays the facility rate, and the CY 2026 Physician Fee Schedule cut facility indirect practice expense RVUs to half the non-facility allocation.
• FY 2027 IPF PPS raises the federal per diem base rate to $912.40 for discharges beginning October 1, 2026.
• The 190-day lifetime limit applies to freestanding psychiatric hospitals and not to distinct-part psychiatric units.