Place of Service Code 22, officially designated as “On Campus – Outpatient Hospital,” is a two-digit code used on the CMS-1500 claim form to indicate where a covered service was rendered. Specifically, it tells the payer that the patient received care at an outpatient department that is physically located on the main campus of a hospital. Think of it this way: a patient walks into a hospital building, checks in at an outpatient department, receives a service from a physician, and leaves the same day. That encounter in most cases would carry POS 22 on the professional claim. The code doesn’t describe what was done. It describes where it happened. That distinction is crucial in medical billing, because payers Medicare in particular calculate reimbursement differently depending on the setting.
What Is POS 22 in Medical Billing?
Where POS 22 Falls in the CMS Place of Service Code List
The Centers for Medicare & Medicaid Services (CMS) maintains a standardized list of place of service codes used across all professional claims in the United States. POS 22 falls within the hospital-based service group, sitting alongside codes like POS 21 (Inpatient Hospital), POS 19 (Off Campus – Outpatient Hospital), and POS 23 (Emergency Room – Hospital).
Each of these codes signals a different care environment, and choosing the wrong one even by one digit can trigger a denial, a payment reduction, or an audit flag. POS 22 specifically identifies a location that is on the main hospital campus but serves patients on an outpatient basis, meaning no overnight admission is expected or planned.
What Does “On Campus – Outpatient Hospital” Mean?
Difference Between On-Campus and Off-Campus Outpatient Services
The distinction between on-campus and off-campus outpatient services became far more significant after the Bipartisan Budget Act of 2015, which changed how off-campus provider-based departments are reimbursed under Medicare. Before that change, many hospitals expanded by building satellite clinics and physician offices far from the main campus, all while billing at higher hospital-based rates.
Today, CMS draws a clear line:
On-campus outpatient (POS 22): The provider-based department is within 250 yards of the main hospital building. These departments continue to receive the higher Outpatient Prospective Payment System (OPPS) rate.
Off-campus outpatient (POS 19): The department is beyond that 250-yard boundary and, unless it was already billing as a provider-based department before November 2, 2015 (a “grandfathered” location), it receives the lower Physician Fee Schedule (PFS) rate.
This difference in rates is not trivial. A procedure reimbursed at $400 under PFS might be reimbursed at $600 or more under OPPS purely because of where the service took place.
How CMS Defines the On-Campus Boundary
CMS uses a geographic standard to define “on campus.” A department qualifies as on-campus if it is located within 250 yards of the main hospital building and that building must be the one registered with CMS as the primary hospital facility. Parking structures, connected wings, and administrative annexes may or may not qualify depending on their physical layout and CMS registration.
Hospitals must accurately track and report their provider-based department locations. When a hospital registers a department with CMS, the location information is tied to specific CMS certification numbers, which then determine the appropriate billing code. For billing staff, this means you should never assume a facility’s location status always verify with your hospital’s compliance or finance department.
When to Use POS 22 in Medical Billing
Services Typically Billed Under POS 22
POS 22 applies to a wide range of outpatient services performed within a hospital’s on-campus outpatient departments. Common examples include:
Outpatient surgery or same-day procedures in a hospital-based surgical suite
Outpatient diagnostic imaging (MRI, CT, X-ray) performed in a hospital radiology department on campus
Lab work and pathology services billed by the ordering or performing physician
Chemotherapy and infusion services administered in a hospital outpatient infusion center
Outpatient rehabilitation sessions (PT, OT, speech therapy) within a hospital-based rehab unit
Outpatient behavioral health visits at a hospital-based psychiatric clinic
Clinic visits at hospital-owned outpatient clinics situated on the main campus
What all these services share is that they occur on the hospital’s registered main campus, and the patient is not admitted as an inpatient. The physician bills a professional fee (on the CMS-1500), while the hospital separately bills the facility fee (on the UB-04).
Which Providers and Specialties Use POS 22
Almost any specialty can use POS 22 if the provider works within a hospital’s outpatient setting. However, it is especially common for:
Oncologists treating patients in hospital-based infusion suites
Surgeons performing outpatient or same-day procedures in hospital ORs
Radiologists interpreting imaging done in hospital departments
Cardiologists conducting stress tests or echocardiograms in hospital-based cardiology clinics
Primary care physicians employed by the hospital and seeing patients in on-campus outpatient clinics
Behavioral health providers working in hospital-based psychiatric or counseling departments
It is especially important for employed physicians those working under a hospital system to understand that their clinic’s location determines the POS code, not their employment status alone.
POS 22 vs Other Place of Service Codes
POS 22 vs POS 19 (Off-Campus Outpatient Hospital)
The difference here comes down to geography. POS 19 applies when a provider-based outpatient department sits more than 250 yards from the main hospital building. Both codes involve hospital outpatient settings, but POS 19 locations are reimbursed at the lower Medicare Physician Fee Schedule rate (unless grandfathered), while POS 22 locations typically receive OPPS rates.
Billing POS 22 when the location is actually off-campus is a compliance risk. It inflates reimbursement above what the location qualifies for and can trigger Medicare audits.
POS 22 vs POS 21 (Inpatient Hospital)
POS 21 applies when the patient has been formally admitted to the hospital as an inpatient typically with an expectation of at least two midnights under the “two-midnight rule.” POS 22 applies exclusively to outpatient encounters. Using POS 21 for a patient who was never admitted or using POS 22 for someone who was creates a significant billing error that payers will almost certainly flag.
POS 22 vs POS 11 (Office Setting)
POS 11 is used when a service is rendered in a physician’s private office that is independent of any hospital. If a cardiologist sees patients at their own private practice, that’s POS 11. If the same cardiologist sees patients at a hospital-owned clinic on the main campus, that’s POS 22. The reimbursement rates differ, and so do the compliance expectations. Physicians transitioning from private practice to hospital employment commonly make errors during this transition by continuing to use POS 11 out of habit.
Billing Rules for POS 22
Payer-Specific Guidelines for POS 22
Medicare follows its own well-documented OPPS and PFS rules for POS 22, but commercial payers each have their own contract terms. Some private insurers mirror Medicare’s methodology; others apply flat rates regardless of setting. A few payers require prior authorization specifically when a service is billed under POS 22, particularly for surgical or high-cost procedures.
Before billing POS 22 to a commercial payer, billing teams should review the provider’s contract and check the payer’s place-of-service policies in their online portals or billing manuals.
Medicare Reimbursement Rules Under POS 22
Under Medicare, when a physician performs a service at a hospital outpatient department, the reimbursement follows a split model:
The hospital bills the facility component under OPPS using a UB-04 claim.
The physician bills the professional component using CMS-1500 with POS 22.
When POS 22 is used, Medicare pays the physician at the facility rate under the Physician Fee Schedule — which is lower than the non-facility (private office) rate. This is because the physician doesn’t bear the overhead cost of running the facility; the hospital absorbs that cost and bills separately for it.
This is a critical point many providers misunderstand. Physicians moving from private practice to hospital employment sometimes expect their personal income to remain the same, not realizing that the facility rate they now receive under POS 22 is lower than the non-facility rate they received under POS 11.
Facility Fee vs Professional Fee Billing
In on-campus outpatient settings, two separate bills typically go out for the same encounter:
Professional fee claim (CMS-1500): Filed by the physician or their group using POS 22.
Facility fee claim (UB-04): Filed by the hospital for the resources, space, staff, and equipment used during the visit.
Patients are sometimes surprised to receive two bills for what felt like one appointment. Transparency about this dual-billing structure is increasingly a focus of patient experience initiatives, and some hospital systems now proactively explain it during registration.
Common POS 22 Billing Errors and How to Fix Them
Wrong POS Code Selection
The single most common POS 22 error is choosing the wrong code in the first place typically confusing POS 22 with POS 11 or POS 19. This often happens when:
A physician recently joined a hospital system and billing staff haven’t updated their templates
A clinic relocated from off-campus to on-campus (or vice versa) without updating billing workflows
A locum tenens provider uses a standard template that doesn’t match the service location
Fix: Maintain a location-to-POS code mapping document that is updated every time a provider’s practice location changes. Assign someone on the billing team to audit POS codes quarterly.
Mismatched Diagnosis and Setting
Some diagnoses are inherently linked to specific care settings. If a claim shows POS 22 but the diagnosis or procedure code points to inpatient-only services, payers will flag the discrepancy. Similarly, using POS 22 for services that require a hospital admission like certain complex surgeries raises immediate red flags.
Fix: Use claim-scrubbing software that cross-references POS codes with procedure and diagnosis codes before submission. Most modern practice management systems include this logic, but only if properly configured.
Claim Denials Related to POS 22 and How to Appeal
Denials tied to POS 22 typically fall into these categories:
Place of service not covered: The patient’s plan doesn’t cover outpatient hospital services, or has a different cost-sharing structure for hospital-based visits.
Incorrect POS for the service: The payer’s system flags the code as inconsistent with the billed procedure.
Duplicate billing: The facility and professional claims overlap in ways the payer interprets as double-billing.
When appealing, always include documentation of the physical location of the service, the hospital’s CMS certification for the department, and a clear explanation of the professional vs facility fee split. Many denials at this stage are reversed when the clinical and administrative context is provided in writing.
POS 22 and Reimbursement Rates
How POS 22 Affects Payment Rates for Physicians
As mentioned, Medicare pays physicians at the lower facility rate when POS 22 is used. The logic is straightforward: the overhead is covered by the hospital’s facility fee. For physicians, this can mean a meaningful reduction in per-claim reimbursement compared to a private office setting.
That said, hospital employment often comes with salary guarantees and benefits that offset this reduction so the net effect on physician income isn’t always negative. But from a pure claims perspective, POS 22 claims consistently pay less to the physician than POS 11 claims for the same service.
Hospital Outpatient Prospective Payment System (OPPS) and POS 22
The OPPS governs how Medicare pays hospitals for outpatient services. Under this system, services are grouped into Ambulatory Payment Classifications (APCs), each with a predetermined payment rate. When a hospital bills for a service tied to a POS 22 encounter, Medicare pays the APC rate which accounts for facility costs including nursing, equipment, and space.
CMS updates OPPS rates annually through the Outpatient Prospective Payment System final rule, typically released each November. Billing teams should review these updates each year to understand how reimbursement for common services may have shifted.
Tips for Accurate POS 22 Billing
Verifying the Correct Place of Service Before Submission
Before any claim goes out, the billing team should confirm:
Is the service location registered with CMS as a provider-based department?
Is it within 250 yards of the main hospital building?
Has the physician’s primary service location been updated in the billing system?
Does the payer accept POS 22 for this specific procedure code?
Building this verification into the claim preparation workflow not as an afterthought, but as a standard step prevents the bulk of POS-related denials before they happen.
Documentation Requirements for POS 22 Claims
Proper documentation for POS 22 claims should establish:
The date and physical location of the service
Evidence that the patient was treated on an outpatient basis (no admission)
The treating provider’s credentials and relationship to the hospital
The medical necessity of the service, as always
For provider-based departments in particular, CMS requires hospitals to notify patients — in writing — that they are being treated in a hospital outpatient department and that they may be responsible for a facility fee in addition to their co-pay. Failure to provide this notice can create compliance exposure for the hospital.
Final Thoughts
POS 22 is one of those codes that looks simple on the surface — just two digits — but carries real financial and compliance weight. Whether you’re a physician joining a hospital system for the first time, a billing manager auditing your team’s workflows, or a coder reviewing your POS code assignments, understanding the rules around on-campus outpatient billing is essential to getting claims right the first time. The key takeaways: know your physical location relative to the main campus, understand how the code affects both facility and professional fee reimbursement, and keep your billing system’s POS assignments updated as provider locations evolve. A little diligence upfront saves significant rework and potential compliance headaches down the line.
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