CMS IOP Billing Guidelines: How to Bill Medicare IOP

Medicare pays for intensive outpatient program (IOP) services as a distinct benefit, in force since January 1, 2024. Every IOP claim carries condition code 92, and your type of bill and payment method follow from what kind of provider you are. Programs running IOP alongside other levels of care need billing built for institutional and professional claims.

TL;DR Medicare IOP is its own benefit, not outpatient therapy billed more often. The claim turns on the condition code, the type of bill for your provider type, and the daily service count that sets your per diem.

Key takeaways

• Condition code 92 is mandatory. It belongs on every Medicare IOP claim, from every provider type, and has since January 1, 2024.
• Type of bill follows the entity, not the service. 13X for hospital outpatient, 85X for critical access hospitals, 76X for community mental health centers. FQHCs, RHCs, and opioid treatment programs bill on their own terms.
• Payment is a per diem set by a count. Three services in a day pays one rate. Four or more pays another.
• Certification is a nine-hour standard. A physician certifies a minimum of nine hours of services per week at admission, then recertifies at least every 60 days.
• The IOP per diem is not telehealth-payable. Remote sessions do not count toward it.

Scope: United States, Medicare fee-for-service. Mental health and substance use IOP. Written for billing leads, coders, and RCM managers at behavioral-health provider organizations. Medicaid and commercial payer rules differ and are out of scope.

---

What Medicare IOP is, and how it differs from PHP

Medicare IOP is a distinct ambulatory benefit for people who need more than routine outpatient therapy but less than partial hospitalization. Section 4124 of the Consolidated Appropriations Act, 2023 established Medicare coverage and payment for it, effective January 1, 2024. Before that, IOP had no Medicare benefit category of its own.

A physician must certify at admission that the patient needs a minimum of nine hours of services per week, evidenced by the plan of care. Partial hospitalization sits above that at a minimum of 20 hours per week. PHP also requires physician certification that the services are taking the place of inpatient hospitalization.

Both thresholds are requirements, not rules of thumb. IOP is not intended for patients who otherwise need an inpatient level of care.

The distinction matters operationally because Medicare treats the two as separate benefits, with separate claims, separate APCs, and an edit that catches you filing both.

Covered IOP services include individual and group psychotherapy, occupational therapy, activity therapy, psychiatric nursing, education and training, diagnostic services, and family counseling whose primary purpose is treating the patient’s condition. Activity therapies have to be individualized and not primarily recreational or diversionary.

Drugs and biologicals are covered only where they cannot be self-administered and are furnished for therapeutic purposes. Self-administered medications are excluded, as are meals, transportation, vocational training, and services furnished to a hospital inpatient.

Who can bill Medicare IOP

Six provider types can furnish it. Type of bill and payment method both follow from which one you are.

Table 1. Medicare IOP by provider type: claim format, payment method, and required claim elements.

Provider type	Claim / TOB	Payment method	Required on the claim
Hospital outpatient department	Institutional, TOB 13X	OPPS per diem: APC 5861 (three services per day) or APC 5862 (four or more)	CC 92; IOP and component revenue codes; HCPCS/CPT lines; PO or PN modifier for off-campus departments
Critical access hospital	Institutional, TOB 85X	Cost-based, not APC	CC 92; revenue codes. HCPCS reporting is not required; report the number of times the revenue-code visit was performed
Community mental health center	Institutional, TOB 76X	OPPS per diem: APC 5851 (three services per day) or APC 5852 (four or more)	CC 92; IOP and component revenue codes; HCPCS/CPT lines
Federally qualified health center	FQHC institutional claim	Separate per-day amount. IOP costs are excluded from the FQHC PPS rate. CY2026: $319.38 for three or fewer services, $418.45 for four or more	CC 92; revenue code 0905; at least one primary IOP service code; all daily IOP charges on the primary service line
Rural health clinic	RHC encounter claim	Separate per-day amount. IOP costs are excluded from the all-inclusive rate	CC 92; revenue code 0905; the CG modifier on the payment line
Opioid treatment program	Professional, CMS-1500 or 837P	Weekly add-on to the bundled payment: HCPCS G0137	A minimum of nine services over a seven-contiguous-day period. Medications, opioid-overdose antagonists, and toxicology testing do not count toward the nine

A common configuration error is mapping the payment method to the service. It maps to the entity. Set claim rules by provider type first, then by service.

Two rows carry consequences for finance. FQHCs and RHCs have to track IOP separately from their normal encounters, because IOP sits outside the rates their other visits are paid under.

CMHC rates also changed. The CY2026 OPPS final rule calculates CMHC costs at 40 percent of final hospital-based IOP costs, for both IOP and PHP. The change corrects an inversion in which three-service days were pricing above four-service days.

What has to be on the claim

Condition code 92

Condition code 92 exists for one purpose. It identifies the claim as intensive outpatient program services. CMS has required it on every Medicare IOP claim since January 1, 2024, from hospitals and CMHCs, with FQHCs and RHCs instructed to report it as well.

It is not contractor-discretionary, so “our MAC hasn’t asked for it” will not hold up. It also has nothing to do with payer sequence, which is a recurring confusion with the Medicare Secondary Payer condition codes. On the UB-04 it goes in the condition code block, FL 18 through 28.

No revenue code identifies a claim as IOP. Condition code 92 does. Programs that build their edits around a revenue code instead will still see claims returned.

Revenue codes

Table 2. IOP revenue codes and the HCPCS/CPT codes reported against them.

Revenue code	Service	Paired HCPCS/CPT
0905	Intensive outpatient services, psychiatric	Component codes below. Required code for FQHCs and RHCs
0906	Intensive outpatient services, chemical dependency	Component codes below
0900	General behavioral health treatment services	As applicable
0904	Activity therapy	G0176
0914	Individual therapy	90832, 90834, 90837
0915	Group therapy	90853, G0410, G0411
0916	Family therapy	90846, 90847
0918	Behavioral health testing	96130, 96131, 96136, 96137
0942	Education and training	G0177
043X	Occupational therapy	G0129
0250	Drugs and biologicals	No HCPCS required

Institutional providers billing substance use IOP report 0906. FQHCs and RHCs report 0905 and should not report IOP under 0900. Opioid treatment programs are the exception in this table, because they bill on a professional claim with G0137 instead of institutional revenue codes.

G0410 and G0411 are national HCPCS group psychotherapy codes, not local-policy curiosities. CMS lists both as permissible group-therapy codes on IOP claims under revenue code 0915, along with 90853. G0411 is the interactive variant.

Three G-codes have scope limits your edits should respect. G0129 (occupational therapy) and G0176 (activity therapy) may be reported only for IOP or PHP. G0177 (training and education) may also be reported in outpatient mental health settings.

Units and time

Unit errors clear most claim scrubs and surface later, in an audit. Finding them there is what makes them expensive.

• 90832 is 16 to 37 minutes. 90834 is 38 to 52 minutes. 90837 is 53 minutes or more. Bill the code the documented start and stop times support, not the code the schedule template says.
• 96130 is the first hour of psychological testing evaluation services and 96131 is each additional hour. The 30-minute codes are different: 96136 is the first 30 minutes of test administration and scoring, 96137 each additional 30 minutes.
• Group therapy is generally one unit per group session per beneficiary. Facilities report the count of service performances per the code descriptor.
• CAHs report the number of times the revenue-code visit was performed instead of HCPCS codes.

Modifiers that apply

Hospitals report PN for non-excepted off-campus provider-based departments and PO for excepted off-campus departments. RHCs report CG on the line carrying the payment.

PN, PO, and CG are the only modifiers with a role here. Anatomical modifiers and professional-component modifiers do not belong on IOP facility lines.

Building the claim, step by step

On the UB-04, six form locators carry most of the IOP-specific content.

1. FL 4, type of bill. 13X, 85X, or 76X per the table above. Take it from the entity, not the service.
2. FL 6, statement covers period. The episode dates for the billing period.
3. FL 18 through 28, condition codes. Condition code 92, every time.
4. FL 42, revenue code. The IOP revenue code plus a component code per service line.
5. FL 44, HCPCS/rate. The procedure code, with modifiers appended here, up to four modifiers of two characters each. Modifiers do not go in FL 45.
6. FL 45, service date. The line-item date of service.
7. FL 46, units of service. Per the code descriptor and any contractor unitization instruction.

Before you transmit, confirm the billing NPI and provider identifiers match your MAC enrollment file. Run the claim through your clearinghouse edits. Make sure the attendance record, session times, and signed plan of care are retrievable for every line you are billing.

Certification, recertification, and the documentation behind them

Most Medicare IOP audits start with certification, because certification cannot be created after the fact.

At admission, a physician certifies that the patient requires a minimum of nine hours of IOP services per week, and the plan of care has to show it. A physician signature is required for hospital, CMHC, FQHC, and RHC IOP; there is no non-physician-practitioner pathway. Opioid treatment programs are the exception, where a physician or a qualifying non-physician practitioner may certify. Certification language that names the hours explicitly is what a reviewer looks for. A plan of care describing three groups a week without stating the weekly hours leaves the certification unsupported.

Copy-ready certification language, with your own fields filled in:

I certify that [patient name, DOB, MRN] requires intensive outpatient program services beginning [date] for a minimum of nine hours per week. Primary diagnosis: [ICD-10]. Clinical rationale: [symptoms, functional impairment, prior treatment, risk factors]. Planned schedule and modality: [sessions per week, length, group and individual]. Measurable goals: [goals]. [Clinician printed name, credential, license number, NPI, signature, date]

Recertification is required at intervals your organization sets, but no less frequently than every 60 days following the initial IOP certification. It has to show continued medical necessity with objective progress, not restate the admission note.

PHP runs on a different clock. The first PHP recertification is required as of the 18th calendar day following admission, then no less frequently than every 30 days.

IOP has no first-recertification deadline, only the 60-day interval. A single shared recertification rule in the EMR will break one of the two programs.

Attendance is the record that ties a billed day to a delivered service. One line per client per session, exportable:

Date | Client name or ID | Time in | Time out | Total time | Modality | Session topic | Clinician name, credential, license, NPI | Clinician signature

Use unambiguous time formats, keep the clinician credential and NPI on the roster itself, and tie every roster row to a progress note in the record. For the documentation standard behind the sessions themselves, see our guides to documenting group therapy sessions for audit and audit-ready treatment plans.

Where Medicare IOP claims break

The service count is wrong. Payment turns on whether a day had three services or four or more, which makes the count a payment variable, not a documentation detail. Capture it at the encounter. A number reconstructed from notes at month end is a number nobody can defend.

PHP and IOP overlap. An IOP claim carrying condition code 92 and a separate PHP claim covering overlapping periods within seven days of each other is returned to the provider, whether or not the PHP claim carries condition code 41. Build the edit on a seven-day window; a same-day check misses most of the exposure.

Certification is missing the hours. A plan of care that does not state the weekly hours is the most common single gap, and no later edit fixes it.

The type of bill does not match the entity. Usually a configuration artifact, and usually caught only after a batch has gone out.

Timely filing runs out mid-appeal. Denials on institutional per-diem claims take longer to work than professional claims, and the filing clock does not pause. For the limits and how they interact with corrected claims, see timely filing limits. For the workflow that keeps denials moving, see our guide to A/R and denial workflows.

RTP reason codes vary by contractor, so confirm the specific code with your own MAC instead of a general reference.

Telehealth and Medicare IOP: what is not payable

The Medicare IOP per diem is not payable as telehealth.

For opioid treatment programs the rule is explicit. The Medicare Claims Processing Manual states that OTPs furnishing intensive outpatient services through audio-video or audio-only communications technology will not receive payment under Part B.

For hospital outpatient departments, CMHCs, FQHCs, and RHCs there is no equivalent prohibiting sentence. The answer comes from the payment structure instead.

The IOP per diem is an OPPS or FQHC/RHC payment triggered by revenue code 0905 and condition code 92. The Medicare Telehealth Services List governs services paid under the Physician Fee Schedule, so a per diem cannot appear on it. There is no telehealth version of the payment to bill.

Expect a coder to raise the counterexample: individual codes you might report inside an IOP, including 90853 and G0410, do appear on the CY2026 telehealth list. Their presence there does not make the IOP per diem telehealth-payable.

Individual behavioral-health services are a separate question, with their own telehealth rules, place-of-service requirements, and modifiers. Our guide to CPT codes and telehealth rules for outpatient mental health services covers those. What you cannot do is count a remote session toward a Medicare IOP per diem or file an IOP claim as telehealth.

Configuring your system for Medicare IOP

Most of what goes wrong here is configuration, not knowledge. Start with these five, and add them to the general questions in our IOP software evaluation criteria.

1. Auto-populate condition code 92 from the IOP level-of-care flag on the encounter, so it does not depend on a biller remembering. Log what triggered it.
2. Set type of bill from the provider record, not from a service mapping, and lock it against per-claim overrides.
3. Capture the daily service count at the encounter, surface it in the claim preview, and store the raw timestamps alongside the computed count for the audit trail.
4. Block submission when an IOP date of service falls within seven days of a PHP claim, and require a documented reason for any override.
5. Place PO, PN, and CG by rule rather than by hand, based on the department or entity attributes already in the record.

Two further edits catch what those five miss. Block transmission when billed group time does not match linked attendance, and put certification and recertification dates on a work queue so a lapsed recertification surfaces before it becomes a takeback.

For how billing and the clinical record connect, see our guide to integrated EHR billing by level of care.

---

Condition code 92 on every claim, type of bill by entity, a service count you can trust, and an edit that catches PHP and IOP overlapping inside seven days. If you would rather have those enforced by the system than by a checklist, see Alleva in action and we will walk your billing team through how the rules get applied.

Where Alleva fits

Alleva is behavioral-health software, so billing sits inside the same system as the clinical record. Its Encounter Transmission Table runs pre-submission validation with rules set per payer and per program. Condition code, type of bill, and service-count logic all belong at that level.

Smart claim scrubbing catches a missing element before the batch goes out. Verification of benefits runs through the Waystar clearinghouse integration at intake, and ERAs post automatically with live claim status.

If you would rather have those rules enforced by the system than by a checklist, see Alleva in action and we will walk your billing team through how they get set per payer and program.

---

Frequently asked questions

What is condition code 92?

Condition code 92 identifies a claim as intensive outpatient program services. It is not a payer-sequence code and it is not a general therapy flag.

Do all Medicare IOP claims need condition code 92?

Yes. CMS has required it on every Medicare IOP claim since January 1, 2024, across provider types. Treating it as contractor-discretionary is one of the most common reasons IOP claims come back.

What type of bill do we use for Medicare IOP?

It depends on what your organization is, not what services you deliver. Hospital outpatient departments use 13X, critical access hospitals use 85X, and community mental health centers use 76X. FQHCs, RHCs, and opioid treatment programs file on their own claim types.

What revenue code is Medicare IOP billed under?

Institutional providers report 0905 for psychiatric IOP and 0906 for chemical-dependency IOP. Component services carry their own revenue codes alongside it, such as 0914 for individual therapy and 0915 for group. FQHCs and RHCs are specifically required to report 0905.

How many hours a week does Medicare require for IOP?

A minimum of nine hours of services per week, certified by a physician at admission and evidenced by the plan of care.

How is Medicare IOP different from PHP?

Intensity and intent. IOP requires a minimum of nine hours per week; PHP requires a minimum of 20. PHP also requires physician certification that the services are replacing inpatient hospitalization, while IOP is not intended for patients who need an inpatient level of care.

Can we bill Medicare IOP as telehealth?

No. For opioid treatment programs the prohibition is explicit in the Claims Processing Manual. Everywhere else, the IOP per diem is an institutional or FQHC/RHC per-diem payment, and the Medicare Telehealth Services List covers Physician Fee Schedule services, so there is no telehealth version of the per diem to bill.

Individual behavioral-health services have their own telehealth rules, but a remote session cannot count toward an IOP per diem.

Can a patient be in PHP and IOP in the same week?

Not on overlapping claims. An IOP claim with condition code 92 and a separate PHP claim covering overlapping periods within seven days of each other will be returned to the provider, whether or not the PHP claim carries condition code 41.

How often does IOP certification have to be renewed?

Recertification happens at intervals your organization sets, but no less frequently than every 60 days after the initial certification. IOP has no first-recertification deadline.

PHP is on a different clock: the first recertification is required as of the 18th calendar day following admission, then at least every 30 days. Do not share one recertification rule across both programs.

Can FQHCs and RHCs bill Medicare IOP?

Yes, and the payment sits outside their usual rates. IOP costs are excluded from the FQHC PPS rate and the RHC all-inclusive rate, and IOP is paid at separate per-day amounts. RHCs also report the CG modifier on the payment line.

Can an opioid treatment program bill IOP?

Yes, as a weekly add-on using HCPCS G0137 on a professional claim. The program has to furnish a minimum of nine services over a seven-contiguous-day period. Medications, opioid-overdose antagonists, and toxicology testing do not count toward that nine.

Do critical access hospitals report HCPCS codes on IOP claims?

No. CAHs are not required to report HCPCS on this benefit. They report the number of times the revenue-code visit was performed, and they are paid on a cost basis instead of through an APC.