POS 52 is the two-digit place of service code for a Psychiatric Facility-Partial Hospitalization.
POS 52 tells the payer that a service was given in a structured day program for mental illness. The patient does not stay overnight.
Centers for Medicare & Medicaid Services (CMS) defines POS 52 as “A facility for the diagnosis and treatment of mental illness that provides a planned therapeutic program for patients who do not require full-time hospitalization, but who need broader programs than are possible from outpatient visits to a hospital-based or hospital-affiliated facility.”
POS 52 carries the facility indicator “F” in the CMS POS database. Physician services to a PHP patient get paid at the facility rate.
The facility rate is lower than the non-facility rate. The non-facility rate is higher because it includes overhead like staff, supplies, and equipment. Under POS 52, the facility absorbs that overhead. The physician fee drops to the facility schedule.
This guide explains POS 52 in medical billing, when to use POS 52, Partial Hospitalization Program requirements, reimbursement, documentation, and common denial risks.
What Is a Partial Hospitalization Program?
A Partial Hospitalization Program (PHP) is a structured outpatient psychiatric program. It runs less than 24 hours per day. The patient lives at home or in a community setting. The patient travels to the program each treatment day.
To qualify as a Medicare PHP, the program must meet four core conditions. The rules come from LCD L37633 and Chapter 6 of the Medicare Benefit Policy Manual.
- At least 20 hours of service per week: Noridian and other MACs state that a PHP must give a minimum of 20 hours of structured therapy per week. The services run under a written plan of care.
- Multidisciplinary team under physician direction: A physician leads the team. The team includes psychologists, social workers, occupational therapists, psychiatric nurses, and other licensed clinicians.
- In lieu of inpatient admission: Patients must either (a) be stepping down from a recent inpatient psychiatric stay, or (b) be at reasonable risk of inpatient admission without the program.
- Active, vigorous treatment. Programs that are mainly social, recreational, or custodial do not qualify. Programs that only try to maintain wellness in chronic patients also do not qualify.
PHP fills the gap between inpatient care and outpatient therapy. It works as a step-down after a psychiatric admission. It also works as a step-up when outpatient visits are not enough to keep a patient safe.
Services Delivered in a PHP
The covered service list in LCD L37633 includes:
- Individual and group psychotherapy by physicians, psychologists, LCSWs, and other licensed clinicians
- Occupational therapy when it is part of the physician’s plan
- Medication management and drugs that cannot be self-administered
- Family counseling tied to the patient’s treatment
- Activity therapy that is clinical, not recreational
- Patient education about the psychiatric condition and its treatment
- Diagnostic services needed for mental health care
Day care, recreation-only programs, vocational training, transportation, meals, and self-administered drugs are not covered PHP services.
Physician Certification Rules
Two documents control PHP billing on the physician side.
- Initial certification at admission: The treating physician must certify in writing that the patient would need inpatient psychiatric care without PHP. The certification states the diagnosis and the need for the program.
- First recertification at day 18: Per LCD L37633, the first physician recertification is due by the 18th calendar day after admission. It must say the patient would still need inpatient care without the program.
- Subsequent recertifications: After the first one, the provider sets the interval. The interval cannot be longer than every 30 days.
When Should You Use POS 52?
POS 52 is used on the professional claim when a physician or licensed clinician treats a patient in a partial hospitalization program at a psychiatric facility. The code reports where the work was done. It does not describe what was done. The CPT or HCPCS code on the claim line still describes the service itself.
Qualifying facility types
POS 52 applies in two settings.
- Freestanding psychiatric facilities that run a partial hospitalization program.
- Hospital-affiliated PHP units that are part of a hospital’s outpatient mental health services. CMS lists POS 52 as valid for physician services in hospital-based PHP. The code pays at the facility rate.
Clinical scenarios that fit POS 52
These services are typically billed under POS 52.
- A psychiatrist runs a diagnostic evaluation (90791 or 90792) on the first day a patient enters the PHP.
- A psychologist gives 45-minute individual psychotherapy (90834) inside the program.
- A psychiatrist runs an E/M visit (99213-99215) for medication management during the program.
- Group psychotherapy (90853) by a licensed clinician as part of the daily PHP schedule.
- Family psychotherapy with the patient present (90847) tied to the treatment plan.
When Should You Avoid Using POS 52?
Several common settings look like PHP but use a different POS code.
- Office-based outpatient therapy: A weekly 60-minute therapy visit in a private office uses POS 11. POS 52 does not apply even if the patient has a serious mental illness.
- IOP-only programs: Programs that run fewer than 20 hours per week do not meet the PHP standard. The correct POS is often 11, 22, or 53.
- Residential settings: A patient who lives at the facility 24 hours a day is in residential treatment. The code is POS 55 (residential SUD) or POS 56 (psychiatric residential).
- Inpatient psychiatric admission: A patient admitted overnight to a psychiatric hospital is billed with POS 51.
Hospital-based PHP versus freestanding PHP
This is one of the most common areas of confusion in PHP billing.
- Freestanding psychiatric facility PHP: bill professional services with POS 52. The facility bills its own claim on the UB-04 (837I). It uses revenue codes 0912 or 0913, HCPCS H0035, and bill type 131.
- Hospital-based PHP (provider-based outpatient unit): physicians may bill professional services with POS 52. CMS lists the code in the hospital-based PHP setting. Some payers and contracts ask for POS 22 (on-campus outpatient hospital) instead. Always confirm with the MAC and the payer’s billing policy first.
What Is the Difference Between POS 52 and POS 51?
POS 51 is for inpatient psychiatric hospitalization. The patient is admitted and stays overnight. POS 52 is for partial hospitalization. The patient is in a structured day program and goes home each evening.
The overnight stay is the single most important factor. If the patient sleeps at the facility, the claim takes POS 51. If the patient leaves at the end of the treatment day, the claim takes POS 52.
The distinction also affects E/M code selection. Inpatient hospital E/M codes (such as 99221-99239) match POS 51. Outpatient E/M codes (such as 99202-99215) match POS 52. PHP patients are outpatients even when the program runs as long as an inpatient day.
POS 52 vs. Other Behavioral Health POS Codes
The behavioral health POS family sits in a narrow range. A single-digit error can route the claim to the wrong fee schedule.
| POS Code | Setting | Level of Care | Facility Indicator |
| POS 51 | Inpatient Psychiatric Facility | 24-hour inpatient psychiatric care | F |
| POS 52 | Psychiatric Facility-Partial Hospitalization | Structured day program, less than 24 hours, at least 20 hours/week | F |
| POS 53 | Community Mental Health Center | Outpatient and partial hospitalization services in a CMHC | F |
| POS 55 | Residential Substance Abuse Treatment Facility | Live-in SUD treatment | F |
| POS 56 | Psychiatric Residential Treatment Center | 24-hour psychiatric residential | F |
| POS 22 | On-Campus Outpatient Hospital | Hospital outpatient department | F |
All six codes carry the F facility indicator. The code you pick still matters. Payers tie each code to specific covered services, modifiers, and revenue code combinations. A claim with POS 51 and a PHP per-diem code does not match. A claim with POS 11 and H0035 does not match either.
Documentation and Compliance Requirements for POS 52
POS 52 claims need a clean documentation chain to survive an audit. The four core documents are listed in LCD L37633.
Initial physician certification
The certification must state in writing that the patient would need inpatient psychiatric care without PHP. It must include the diagnosis, the psychiatric need for the program, and the physician’s signature. The signature must be on or before the day of admission. A missing or undated certification is one of the fastest paths to a full PHP denial.
Individualized treatment plan
The plan of care must be written and signed by the physician. Per the LCD, it must:
- identify measurable, time-framed treatment goals
- address the presenting psychiatric symptoms directly
- evaluate and measure response to treatment
- describe how services are coordinated across the team
- document progress toward discharge or the continued need for PHP intensity
Progress notes
PHP progress notes must show the type of treatment service, the patient’s response, and how that response ties back to the goals in the treatment plan. Notes must correlate with the services billed on each date.
Recertification timing
Two specific dates anchor the recertification schedule.
- Day 18 from admission: The first recertification is due no later than the 18th calendar day after admission. It must be signed by a physician who treats the patient and knows the response to treatment.
- Every 30 days after that: Later recertifications must be done at least once every 30 days. Some providers set shorter intervals.
Each recertification must describe the patient’s response to therapy. It must list the symptoms that keep the patient in PHP. It must also state the plan for discharge.
OIG audit risk areas
PHP and POS 52 services sit on the OIG enforcement work plan year after year. Recurring findings include:
- Admissions of patients who do not meet eligibility (no inpatient-level need, or unable to benefit from active treatment)
- Services billed without records showing they were ordered, signed, dated, and clinically necessary
- Day care, recreational, or social activities billed as PHP
- Missing or late physician recertification at day 18 or day 30
False Claims Act exposure
A PHP claim with a place of service code that misrepresents the actual setting can be treated as a false claim under 31 U.S.C. § 3729. One well-known example is the Riverside General Hospital case, where PHP claims were submitted for services that did not meet medical necessity requirements and included ineligible patients. The case highlights how using PHP billing codes for services that do not qualify can lead to significant civil and criminal penalties.
Common POS 52 Billing Errors and Denials
Most POS 52 denials happen because the place of service does not match the procedure code or the claim details.
- Using inpatient E/M codes: Do not bill inpatient E/M codes (99221-99223, 99238-99239) with POS 52. Use outpatient E/M codes (99202-99215) or the appropriate psychotherapy codes instead.
- Using the wrong POS code: POS 52 is for Partial Hospitalization Programs (PHP). Do not confuse it with POS 51 (inpatient psychiatric) or POS 22 (hospital outpatient visit).
- Missing physician certification: Claims may be denied if the initial certification or required recertifications are missing, late, unsigned, or incomplete.
- Revenue code and HCPCS mismatch: On UB-04 claims, revenue codes 0912/0913 should be paired with the correct HCPCS code (such as H0035) and the appropriate bill type.
- Not meeting PHP requirements: Patients must receive at least 20 hours of structured therapy per week to qualify for PHP. Otherwise, use the appropriate IOP or outpatient billing.
- Payer-specific rules: Some insurers, including Optum/United Behavioral Health and certain Blue Cross Blue Shield plans, have additional billing requirements. Always verify each payer’s billing guidelines before submitting the claim.
Pre-submission Checklist for POS 52 Claims
Before a POS 52 claim leaves the system, confirm these items:
- POS 52 is in Box 24B for every PHP service line
- The CPT/HCPCS code matches an outpatient PHP service, not an inpatient code
- The initial physician certification is on file, signed, and dated on or before admission
- The first recertification is dated no later than day 18
- The treatment plan is signed by the physician and updated with measurable goals
- Progress notes for each billed date describe the service, the response, and the tie to plan goals
- For institutional claims, revenue code 0912 or 0913 pairs with H0035 and bill type 131
- The professional claim’s POS matches the institutional claim’s revenue codes
Final Words
POS 52 is used for services provided in a Psychiatric Facility Partial Hospitalization Program (PHP). Using the correct place of service code, meeting PHP eligibility requirements, and maintaining complete documentation are essential for accurate reimbursement and compliance. Before submitting a claim, confirm that the POS code, CPT or HCPCS codes, physician certifications, and treatment records all support the service provided. A careful review before submission can help prevent denials, audits, and payment delays.
