HCPCS code H0040 – Assertive community treatment program

Key takeaways

H0040 is a per-diem HCPCS Level II code for assertive community treatment (ACT) programs, and one unit equals one calendar day of ACT services.

Room and board is excluded from H0040 and may only be billed separately where the state plan allows it.

Missing prior authorization, incomplete daily service logs and incorrect modifiers are three of the most common reasons H0040 claims are denied.

Pabau, the practice management platform we build, offers claims management and digital documentation tools that help behavioral health providers keep per-diem documentation complete.

HCPCS code H0040: Definition and official descriptor

HCPCS code H0040 carries the official descriptor Assertive community treatment program, per diem.

It sits in the H-series of HCPCS Level II codes, which the Centers for Medicare and Medicaid Services (CMS) maintains. H-codes cover behavioral health and substance abuse treatment services, and state Medicaid agencies are their main users.

ACT programs serve adults with serious mental illness who need intensive, community-based support that falls short of inpatient care. A qualifying ACT team typically includes a psychiatrist or psychiatric nurse practitioner, case managers, nurses, vocational rehabilitation specialists, and peer support workers. Services are delivered in community settings rather than clinic offices.

What H0040 covers and what it excludes

The per-diem structure means the code bundles all ACT services delivered on a given day into a single billable unit. Knowing what falls inside and outside that bundle is critical for compliance.

Covered services

• 24-hour crisis support and supervision coordination
• Psychiatric assessment and medication management by ACT team members
• Individual and group therapeutic interventions delivered in the community
• Case management, care coordination, and service planning
• Community integration activities (employment support, housing liaison, social skills)
• Daily living skills support and psychoeducation
• ACT team meetings and coordination activities on days the patient receives services

Explicit exclusions

• Room and board: excluded from H0040. These costs may be separately billable under some state Medicaid plans but are never bundled into this code.
• Inpatient services: H0040 is a community-based code. Inpatient psychiatric stays bill under DRG or per-diem inpatient codes.
• Services billed under a separate encounter code: a same-day physician visit billed with a CPT E/M code stays on its own claim line. Never rebundle it into H0040.
• Transportation: billed separately under applicable HCPCS transportation codes where covered.

Overbilling room and board within H0040 is one of the more common audit findings for ACT programs. State Medicaid auditors cross-reference residential cost reports against H0040 claims to identify improper bundling.

H0040 vs. related codes: Avoiding confusion

H0035 is the code coders most often confuse with H0040. Both serve adults with serious mental illness, but the service model and billing structure differ significantly.

The distinction between H0040 and H0035 hinges on ACT program certification. To bill H0040, the provider must operate a state-certified ACT program that meets SAMHSA fidelity standards. H0035 partial hospitalization programs don’t carry the same certification requirement. Billing H0040 without certified ACT status is a compliance violation as well as a coding error.

Documentation requirements for H0040 claims

H0040 claims are per-diem claims, so every billed day must be supported by a service record for that specific date. Payers audit ACT programs by pulling daily logs and matching them against submitted claim dates. A billed date with no matching log is denied, or recovered later in an audit.

The checklist below shows what has to be true for a single billed day to pay.

Required documentation for each billed day typically includes the following elements, though state Medicaid plans may add requirements:

• Individualized treatment plan (ITP): current, signed by a licensed clinician and reviewed at least every 90 days. The ITP must justify ACT-level care.
• Daily service log: records each service contact on the billed date, identifying the team member, the type of service, location, and duration. Auditors usually pull this document first.
• Progress notes: clinically meaningful notes tied to treatment plan goals. Templated notes with no individualization are a denial and audit risk.
• ACT team meeting records: documentation that the interdisciplinary team reviewed the patient’s status, especially relevant for days where community contact is the primary service.
• Eligibility documentation: evidence the patient meets the state’s serious mental illness (SMI) criteria for ACT enrollment.
• ACT program certification: the billing provider must hold current state certification as an ACT program. Certification documents should be on file.
• Physician or prescriber oversight sign-off: some Medicaid plans require that the supervising psychiatrist or psychiatric NP co-sign or review records at defined intervals.

Structured daily note templates make it harder for staff to skip a required field. Missing or vague service logs that can’t support the per-diem unit are among the most frequent audit findings for ACT programs.

Payer requirements and prior authorization

H0040 is primarily a Medicaid code. Medicare publishes no national rate for it, so don’t assume a Medicare or Medicare Advantage plan will pay without checking its coverage policy.

Prior authorization requirements vary by state and managed care organization. As a general pattern:

• Initial enrollment authorization: most state Medicaid plans and MCOs require prior authorization before the first billed day. Authorization typically covers a 90- to 180-day period, renewable on review.
• Continued-stay reviews: ongoing authorization is required at intervals set by the payer. Documentation supporting medical necessity for continued ACT-level care must be submitted.
• Commercial insurers: some commercial plans cover H0040 under behavioral health benefits, but coverage is not universal. Verify each plan’s behavioral health fee schedule before assuming reimbursement.
• Managed care organizations (MCOs): Medicaid MCOs often have their own prior authorization portals and timelines. An MCO authorization does not automatically align with the fee-for-service Medicaid plan’s rules.

Point32Health issued a billing update for PACT services effective December 2025, a sign of how ACT policy keeps shifting payer by payer. Always verify current authorization requirements directly with the payer before submitting a batch of H0040 claims. A written prior authorization process keeps renewal dates from slipping between continued-stay reviews.

H0040 fee schedule and reimbursement rates

H0040 reimbursement rates vary by state Medicaid plan, MCO contract, and calendar year. There’s no single national rate, and Medicare doesn’t publish one for H0040. State Medicaid agencies set base per-diem rates, and MCOs may negotiate different rates under their contracts with ACT providers.

To find current rates, use these sources:

• State Medicaid fee schedule: each state publishes its own fee schedule. Search your state’s Medicaid agency website for the behavioral health or HCPCS fee schedule file.
• MCO provider manual: if the patient is in a managed care plan, the MCO provider manual or fee schedule addendum contains the contracted rate.
• Payerprice.com: a 2026 H0040 fee schedule is available via commercial fee schedule databases, which can serve as a benchmark reference. Treat commercial database figures as indicative until confirmed against the official state plan.

State per-diem rates for H0040 reflect the bundled nature of the code. They cover staff salaries, psychiatric oversight, and community services, but not room and board. Because ACT programs are cost-intensive, some states pay enhanced per-diem rates tied to ACT fidelity scores. Review your state’s behavioral health rate schedule each year, since rates typically update on the state fiscal year.

For a broader foundation on how reimbursement works in behavioral health, medical billing fundamentals walk through the claim lifecycle from submission to remittance.

Modifiers used with H0040

Modifier requirements for H0040 differ by payer. Some state Medicaid plans and MCOs require one or more modifiers on every H0040 claim. A wrong or missing modifier often gets the claim rejected outright. A rejected claim never reaches adjudication, so it has to be corrected and resubmitted.

Modifier stacking rules, meaning how many modifiers can appear on one claim line and in what order, are payer-specific. Always consult the MCO or state Medicaid provider manual before stacking modifiers on H0040. The AAPC HCPCS code reference lists standard modifier definitions, but payer-specific applicability overrides the generic definition.

Common reasons H0040 claims are denied

The per-diem structure makes every claim date a potential audit point. The table below pairs each common denial reason with the step that prevents it. A wider denial management process catches the claims that still come back.

How to bill H0040 correctly: Step-by-step

The following workflow applies to standard Medicaid and MCO billing for H0040. Payer-specific variations apply and should override any step below when they conflict.

1. Verify eligibility and ACT enrollment. Before billing any date of service, confirm the patient is enrolled in the Medicaid plan and meets SMI criteria. Then check they’re actively enrolled in a state-certified ACT program.
2. Obtain prior authorization. Submit the PA request with the required clinical documentation (ITP, SMI determination, medical necessity statement). Record the authorization number, authorization period start and end dates, and any visit limits.
3. Confirm ACT program certification is current. The billing NPI must correspond to a certified ACT program. Billing under an uncertified NPI is a compliance violation regardless of service quality.
4. Complete daily service documentation. Ensure daily service logs and progress notes are completed for each date of service before the claim goes out.
5. Assign the correct modifier. Check the payer’s current provider manual. Apply required modifiers in the correct order on the claim line.
6. Submit one unit per calendar day. Bill H0040 with one unit per day. Do not submit multiple units for multiple service contacts within the same calendar day.
7. Reconcile the remittance advice. When the ERA arrives, match paid days against submitted days. Any denied day needs a documented root cause before resubmission or appeal, such as missing documentation, a modifier error, or a lapsed authorization.

ACT programs with large caseloads benefit from claims management software that tracks every per-diem claim from submission to payment. Building per-diem claims by hand at scale is a steady source of unit errors.

How Pabau supports ACT program billing

ACT teams deliver care out in the community, and every billed day still needs a record behind it. When notes live on paper or in separate tools, matching logs to claim dates becomes a weekly reconciliation job.

Pabau keeps structured notes, digital forms, and claims tracking in one system. Your team can build a daily service log template with fields for the team member, service type, location, and duration. Each note is stored in the patient record alongside the treatment plan.

That turns the weekly pre-submission audit into a review of one system instead of three. Your billing team can check each claim date against its log before the claim goes out.

Keep ACT documentation and claims in one place

Pabau brings structured service notes, digital forms, and claims tracking together, so every H0040 claim date has a record behind it.

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Conclusion

Get the per-diem mechanics right before you chase a better rate. One unit per calendar day, a service log for every billed date, and an authorization covering it will head off the denials covered above.

The trade-off is effort up front. Same-day logs and weekly pre-submission audits take staff time, but they cost less than reworking a denied billing period later.

If your team still reconciles logs and claims across separate tools, fix that first. Book a demo to see how Pabau keeps ACT service notes and claims tracking in one system.

Continue your research

Need to understand behavioral health claims workflows? Revenue cycle management in healthcare covers how to structure billing operations for complex, recurring programs.

Billing other community mental health services? HCPCS code H0036 explains how community psychiatric supportive treatment is billed.

Running a community support program alongside ACT? HCPCS code H2015 covers billing for comprehensive community support services.

Want H0040 claims accepted on the first pass? What is a clean claim breaks down what a claim needs to clear payer edits.

Frequently asked questions