Substance Use Treatment Billing

Substance abuse billing services for every level of care

Fastora provides substance abuse billing services for outpatient programs, intensive outpatient and partial hospitalization programs, detox and residential providers, and office-based and opioid treatment programs. Substance use disorder billing differs from other mental health services because care is billed by level, often with per diem or program codes, under federal confidentiality rules and close utilization review.

Addiction treatment billing also varies by state more than most specialties, because Medicaid programs define many of the codes, modifiers and daily unit limits. A code that pays per diem in one state may be billed in 15-minute units in another, so SUD billing starts with a payer-by-payer code matrix rather than a generic fee schedule.

A single client may move from residential care to partial hospitalization, then to IOP and standard outpatient care within a few months. Each move brings a new authorization, different codes and sometimes a different claim form.

Levels of care we bill and the ASAM Criteria

Many payers use the ASAM Criteria, published by the American Society of Addiction Medicine, or a similar framework to decide which level of care is medically necessary. The criteria assess a client across several dimensions and match them to a level on a continuum from outpatient to residential and inpatient care.

Documentation at each level must show the dimensions that justify it. When a reassessment supports a step down, billing has to change on the same date.

Detox billing: withdrawal management codes

Detox billing depends on two questions: whether the setting is residential or outpatient, and whether the withdrawal is managed at an acute or sub-acute intensity. The HCPCS H-code series separates these, and payers that accept H-codes usually expect the code to match both the setting and the intensity in the authorization.

Many commercial plans and hospital-based programs bill detox on an institutional claim with revenue codes instead, and physician visits during withdrawal management are billed separately with E/M codes. Detox stays are usually approved a few days at a time, so the authorization end date and the next review date matter as much as the code.

IOP/PHP coding and other HCPCS codes for substance abuse billing

Many state Medicaid programs and some commercial plans use HCPCS H-codes for addiction services, while others require CPT psychotherapy codes. The descriptors below are the national HCPCS definitions; each payer decides whether and how it accepts them.

Programs billing on an institutional claim add revenue codes, and some payers require a specific revenue code paired with a HCPCS code for each level of care. Some commercial plans accept S-codes for per diem program services. Medicaid programs vary by state in the codes they cover, the modifiers that identify clinician credentials and the units allowed per day, so we build a payer matrix for each program.

Intensive outpatient program billing

For IOP billing, H0015 describes a program of at least 3 hours a day and at least 3 days a week based on an individualized treatment plan. The note for each program day should show attendance, hours and the services delivered, because payers deny program days that fall short of the minimum hours or lack a current treatment plan.

Partial hospitalization billing

PHP billing is more intensive and more often institutional. Medicare covers partial hospitalization through hospital outpatient departments and community mental health centers, and from 2024 also added an intensive outpatient program benefit in those settings and in rural health clinics and federally qualified health centers, billed on institutional claims under CMS's own requirements. Commercial and Medicaid PHP billing usually uses per diem codes and revenue codes that the payer's contract specifies.

Utilization review and authorizations

Higher levels of care almost always need authorization before admission or within a short window after it. Approval usually covers a limited number of days or sessions, followed by concurrent review, where the program's utilization review staff present updated clinical information to extend care.

Billing and clinical teams need to work from the same calendar. We track approved days by level, the next review date and the authorization number, and hold claims that fall outside an approved span until the gap is resolved. Our prior authorization services support the request paperwork, while clinical reviews stay with your clinicians.

Programs that look for utilization review services for addiction treatment usually need two things: a clinician who can present the case to the payer's reviewer, and a billing team that turns each decision into the right claims. We support the second part and the paperwork around the first. For each client we log the level of care requested, the days or sessions approved, the reviewer's next date, any step-down decision and the appeal deadline if care is denied.

• Admission authorizations requested with the assessment and ASAM dimensions the payer asks for
• Approved spans tracked so no day is billed outside them
• Review dates sent to the program's clinical team ahead of time
• Denied days logged with the reason and the payer's appeal deadline
• Step-downs mirrored in billing on the same date the level of care changes

MAT & OTP billing

Medication assisted treatment billing depends on the setting. Opioid treatment programs certified to dispense methadone bill program services, and Medicare pays enrolled OTPs through weekly bundled payments that cover the medication and related counseling and services. Medicaid and commercial plans may use H0020 or their own program codes, which is why opioid treatment program billing needs a separate code map for each payer.

The Medicare OTP code set runs from G2067 to G2080 and includes bundles for other medications and add-ons for take-home supplies. CMS publishes the current descriptors and payment rates on its OTP billing and payment pages, and updates them through the annual physician fee schedule rule, so we check that page rather than relying on last year's figures.

Office-based practices that prescribe buprenorphine usually bill E/M visits, with counseling billed separately when delivered, while the drug is dispensed through a pharmacy. Federal law no longer requires a separate waiver to prescribe buprenorphine for opioid use disorder. Extended-release injectables given in the office are billed with a HCPCS drug code and an administration service, and often need authorization and NDC reporting.

For MAT billing in office-based practices, the most common denials come from drug units that do not match the HCPCS code definition, a missing NDC or an expired authorization for an injectable. We check those three items on every claim.

Part 2 confidentiality

Federally assisted substance use disorder programs are subject to 42 CFR Part 2, which protects patient records more strictly than HIPAA in several respects. A 2024 final rule aligned Part 2 more closely with HIPAA, including a single patient consent for future uses and disclosures for treatment, payment and health care operations, and HIPAA-style breach notification, with compliance required by February 16, 2026.

The rule keeps a key protection: SUD records cannot be used to investigate or prosecute a patient without written consent or a court order. For billing, claims and payer communications must stay within what the patient's consent allows. Fastora's workflows are aligned with HIPAA and HITECH, with encryption, secure server environments, strict access controls and regular internal audits. Consent policies and legal interpretation of Part 2 remain with the program and its counsel.

Common drug rehab billing denials

• Days billed beyond the approved span after a concurrent review was missed
• Level-of-care code that does not match the authorization
• Per diem and per-session codes on the same day that the payer treats as duplicate
• Missing or incorrect credential modifiers on Medicaid claims
• Group counseling units above a payer's daily limit
• Claims sent to the wrong managed care plan or carve-out administrator

Each denial is logged by reason and payer, so patterns show up in monthly reporting. Our denial management process covers corrected claims and appeals, and our IOP and PHP billing codes guide explains the program codes in more depth.

Substance abuse credentialing and facility enrollment

Programs usually need facility-level enrollment and individual clinician credentialing. State licensing and certification of the facility and its levels of care are the program's responsibility, and payers typically ask for those licenses, accreditation documents and clinician credentials before contracting.

Fastora supports the enrollment paperwork through a tracked nine-stage process, from document collection and NPI and CAQH setup to payer applications, follow-ups and final approval. Counselors who meet CMS requirements may also enroll with Medicare as mental health counselors. See our credentialing services and the wider mental and behavioral health specialties we serve.

What to look for in a billing partner

Substance use billing work is different enough that general billing experience is not always transferable. When you compare billing partners, ask how they track concurrent review, how they build a code matrix for each payer, and how they handle consent limits on SUD records.

Fastora works inside your existing EHR/PM system under the user access you grant, with no software to install and no hidden setup fees. Every claim is handled by certified medical billing and coding professionals and passes through Advanced Pre-Submission Claim Review before submission. Each program has a dedicated account contact, transparent dashboards, monthly performance reporting and a monthly review call.

Fastora quotes after a free billing assessment, and pricing may be a percentage of collections, a flat fee per claim or a hybrid, depending on scope. See our pricing page for how each model works.

Level-of-care coding for intensive outpatient and partial hospitalization programs is covered in IOP and PHP billing codes.