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SAMHSA Aligned · Reviewed 2026-05-12 · MHPAEA Parity Verified

Medicare PHP Coverage: Partial Hospitalization Under Part B

Name: Medicare PHP Coverage: Partial Hospitalization Under Part B
Published: 2026-05-12

Coverage details, prior authorization, copays, network rules, appeal rights, and ASAM Level coverage for Medicare plans seeking Partial Hospitalization Program (PHP).

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Reviewed by RehabHive Editorial Team · Last updated 2026-05-12

Evidence-based

Medicare Part B covers Partial Hospitalization Programs (PHP) at ASAM Level 2.5 when the patient has been previously hospitalized or is at imminent risk of hospitalization. PHP provides 20+ hours/week intensive clinical programming while patient sleeps at home — typically 5 days/week × 4-6 hours. Medicare Part B coinsurance 20% after 0 annual deductible (2026), unless Medigap supplement covers all Part B coinsurance. Medicare Advantage plans typically -0 per PHP session copay. CMS requires PHP delivered at hospital outpatient department or freestanding facility with hospital affiliation.

SAMHSA & NIDA sourced ASAM Criteria 4ed MHPAEA Verified View 6 sources

ASAM Levels Covered

Medicare aligns its coverage with the American Society of Addiction Medicine (ASAM) Criteria, the national standard for matching patients to the appropriate intensity of care.

ASAM Level	Covered	Coverage Notes
2.1 IOP	Yes	Part B coverage since 2024 SUPPORT Act 2.0 expansion
2.5 PHP	Yes	Part B benefit; standard 20+ hours/week, patient hospitalized previously or at imminent risk
3.1 Low-Intensity Residential	No (Original) / Limited (MA)	Original Medicare does not cover; select MA plans add supplemental coverage
3.5 Medium-Intensity Residential	No (Original) / Limited (MA)	Same as 3.1
4-WM Hospital Detox	Yes	Part A; preceding PHP transition

Prior Authorization

Original Medicare no prior auth

Original Medicare Part B does not require prior authorization for PHP. CMS requires PHP delivered by Medicare-enrolled provider at hospital outpatient department or freestanding facility with hospital affiliation. Patient must meet medical necessity criteria: previously hospitalized or at imminent risk of hospitalization without PHP intensity.

Medicare Advantage prior auth

Medicare Advantage plans typically require prior authorization for PHP. MA plans apply ASAM-equivalent medical necessity criteria. Standard turnaround 72 hours non-urgent, 24 hours urgent under CMS rules.

Documentation requirements

For Original Medicare PHP: clinician documents medical necessity (previously hospitalized within 60 days, currently psychiatric symptoms require structured day program, would otherwise require inpatient hospitalization). Part B claims submitted with appropriate CPT/HCPCS codes (H0035 for SUD PHP service).

Cost-Sharing

Original Medicare Part B cost-share 2026

0 annual Part B deductible 2026. After deductible, 20% coinsurance on Medicare-approved amount for each PHP day. Typical PHP daily rate: 0-0; member 20% = -0/day. 4-week PHP (20 days × 0 average coinsurance) = ,000 plus deductible.

Medigap supplement cost

Medigap Plan G covers all Part B coinsurance — effectively public function index() out-of-pocket for PHP after Medigap deductible covered. Plan G monthly premium 0-0.

Medicare Advantage cost-share

MA plans typically charge -0 per PHP session copay or fixed daily cost. UnitedHealthcare, Aetna, Humana, BCBS Medicare Advantage all similar. Annual cost typically public function index(),500-,000 for 4-6 week PHP under MA plan vs ,000+ Original Medicare without Medigap.

In-Network vs Out-of-Network

Original Medicare provider access

Original Medicare allows any Medicare-enrolled PHP provider at hospital outpatient department or freestanding facility with hospital affiliation. CMS Provider Compare tool identifies Medicare-enrolled facilities.

Medicare Advantage networks

HMO MA plans require in-network PHP except true emergencies. PPO MA plans allow out-of-network at reduced coverage. Verify your specific MA plan's PHP network before admission.

Freestanding PHP availability

Medicare requires PHP delivered at hospital outpatient department or freestanding facility with hospital affiliation. Pure freestanding non-affiliated PHP facilities may not accept Original Medicare. Verify Medicare-enrollment status before admission.

Step-Therapy & Fail-First

No step-therapy under Original Medicare

Original Medicare does not apply step-therapy to PHP. CMS medical necessity criteria control: previously hospitalized or at imminent risk of hospitalization required for PHP coverage.

Medicare Advantage criteria

MA plans may apply ASAM-equivalent medical necessity criteria (similar to commercial step-therapy in effect). MA plans typically accept PHP as step-down from hospital or step-up from outpatient when clinical justification documented.

Hospital admission prerequisite

CMS PHP eligibility specifically requires: recent hospitalization OR imminent risk of hospitalization without PHP. Patients with mild-moderate SUD requiring IOP intensity but not hospital-eligible are referred to IOP (also Medicare Part B covered since 2024 SUPPORT Act 2.0).

Federal Parity (MHPAEA) Protections

MHPAEA limited Original Medicare applicability

MHPAEA does not directly apply to Original Medicare (federal program). CMS coverage rules apply uniformly. Medicare Advantage plans subject to CMS parity rules requiring SUD benefits comparable to medical-surgical.

Medicare Advantage 2024 enforcement

CMS 2024 MA Final Rule strengthened parity enforcement on MA plans. MA plans cannot impose more restrictive limits on PHP than comparable medical-surgical day programs. File MA parity complaints at 1-800-MEDICARE.

Real-World Example

Patient situation

A 68-year-old Original Medicare beneficiary with Medigap Plan G in Ohio transitioned from 5-day hospital detox to PHP at hospital outpatient department for severe alcohol use disorder with co-occurring depression. Naltrexone initiated during detox continued through PHP.

PHP course

4-week PHP at hospital outpatient department, 5 days/week × 5 hours = 20 hours/week. Psychiatry consultation 1×/week, group therapy 4 hours/day, individual therapy 1 hour/day. Naltrexone monthly via outpatient prescriber.

Cost outcomes

Total Part B charges for 4-week PHP: ,000 facility billing. Medicare paid 80% = ,200. Member 20% coinsurance = ,800; Medigap Plan G paid all ,800. Member out-of-pocket: public function index() + Medigap monthly premium (5). Discharge from PHP to Part B IOP step-down at hospital outpatient. Sustained recovery at 12-month follow-up.

Composite example for educational purposes; not a guarantee of coverage. Verify your specific plan benefits.

Frequently Asked Questions

Does Medicare cover partial hospitalization?

Yes. Medicare Part B covers Partial Hospitalization Programs (PHP) when patient has been previously hospitalized or is at imminent risk of hospitalization without PHP intensity. PHP must be delivered at hospital outpatient department or freestanding facility with hospital affiliation.

How much does Medicare PHP cost?

Part B 20% coinsurance after 0 annual deductible (2026). Typical PHP daily rate 0-0; member 20% = -0/day. 4-week PHP roughly ,000 without supplement. Medigap Plan G eliminates Part B coinsurance — effectively public function index() out-of-pocket. Medicare Advantage typically -0 per PHP session.

Does Medicare require prior auth for PHP?

Original Medicare does not require prior authorization for PHP. Medicare Advantage plans typically require prior auth. Standard MA turnaround 72 hours non-urgent, 24 hours urgent under CMS rules.

What is the requirement for Medicare PHP eligibility?

CMS requires: (1) patient previously hospitalized for psychiatric or SUD condition within recent period (typically 60 days), OR (2) currently at imminent risk of hospitalization without PHP intensity. PHP is not appropriate for mild-moderate SUD without hospitalization history — those patients typically referred to IOP or outpatient.

Does Medicare cover MAT during PHP?

Yes. MAT covered concurrently with PHP. Buprenorphine under Part D ( public function index()- generic 2026). Methadone for OUD under Part B at SAMHSA-certified OTPs (separate from PHP facility billing). Vivitrol injections under Part B as provider-administered medication.

Does Medigap cover PHP?

Medigap supplements (Plan G, Plan F grandfathered) cover all Part B coinsurance — including PHP 20% coinsurance. With Medigap, PHP out-of-pocket effectively public function index() after Part B deductible covered. Plan G premium 0-0/month.

Can I do PHP without prior hospitalization?

Medicare requires recent hospitalization OR imminent hospitalization risk for PHP eligibility. If neither applies, patient typically referred to Medicare Part B IOP (since 2024 SUPPORT Act 2.0 expansion). Discuss with treating physician — clinical documentation can demonstrate imminent risk criteria.

Does Medicare Advantage cover PHP differently?

MA plans must cover everything Original Medicare covers including PHP under CMS medical necessity rules. MA typically requires prior authorization (Original Medicare does not). MA cost-share typically -0 per PHP session copay vs Original Medicare 20% coinsurance.

How do I find a Medicare-enrolled PHP?

Use CMS Provider Compare tool at medicare.gov/care-compare for Medicare-enrolled PHP providers. SAMHSA Treatment Locator (findtreatment.gov) filter "Partial hospitalization/day treatment" identifies all PHP facilities; verify Medicare enrollment. For MA members: use plan-specific provider directory.

Are appeals available for Medicare PHP denials?

Yes. Original Medicare: standard appeals process (Redetermination → Reconsideration → ALJ → Appeals Council → Federal Court). Medicare Advantage: appeal through plan first. Urgent inpatient or imminent-risk cases get expedited 72-hour review.

Sources & Citations

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Verify Your Medicare Coverage

Call the SAMHSA National Helpline 24/7 (free, confidential) or use our directory to find Medicare-network facilities offering Partial Hospitalization Program (PHP).

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Last reviewed: 2026-05-12 · RehabHive Editorial Team · Based on publicly available Medicare coverage policies, SAMHSA guidelines, and federal MHPAEA regulations.

This information is educational and does not constitute insurance advice. Verify your specific plan benefits directly with Medicare before making treatment decisions.