Substance Abuse Billing Codes: The Working Reference for Treatment Programs

Substance abuse treatment is the only specialty in American healthcare that bills in three code languages at the same time. A program can send a CPT psychotherapy claim (90834) to a commercial plan in the morning, an H0015 per diem to Medicaid before lunch, and a UB-04 institutional claim carrying revenue code 0906 to another commercial payer that afternoon. Cardiology never does this. Neither does orthopedics. Addiction treatment programs live with it on every billing day. The split is structural, not accidental. CPT codes come from the AMA and dominate commercial professional claims. The HCPCS Level II H-codes exist because state Medicaid programs fund an enormous share of addiction treatment and needed codes for services CPT never described: a detox day, a halfway house bed, a methadone dose. Revenue codes enter the picture because facility-based programs bill institutional claims, and institutional payers want to know the setting and department, not just the service. One variable decides which language a claim speaks: the payer. That is also why this reference is organized by level of care instead of numerical code order. Programs think in levels. A clinical director asks whether a patient belongs in IOP or PHP, not whether the service is an H0015 or an H0035. The billing office has to translate that clinical decision into whichever code set the payer on file accepts, and get the units right while doing it. Keep this page open in a tab. It runs from assessment through residential, then closes with the authorization discipline that keeps the codes paid. And if you would rather hand the translation problem to people who work it daily, that is exactly what our substance abuse billing services cover.

Every admission begins with an assessment, and the assessment already forces the language choice. On the CPT side, 90791 covers the psychiatric diagnostic evaluation and 90792 covers the same evaluation with medical services, which means a prescriber performed it. Use 90792 when a physician or psychiatric NP completes the intake and addresses medication; use 90791 for a therapist-level evaluation. Medicaid programs frequently want H0001 instead, the alcohol and drug assessment code, sometimes alongside 90791 and sometimes replacing it, depending on state rules. Screening and brief intervention (SBIRT) has its own three-way split, and it is the cleanest illustration of the payer-determines-code rule in the entire specialty. Commercial plans take 99408 and 99409. Medicare swaps in G0396 and G0397. Many state Medicaid programs use H0049 for the screen and H0050 for the brief intervention. The service is identical in the chart. The code changes with the insurance card. Ongoing medication management in office settings runs through the standard E/M family, 99202 through 99215, the same codes a primary care office bills. Programs with prescribers on staff use these constantly for buprenorphine follow-ups and psychiatric med checks (more on MAT below). A practical note from years of chart audits: payers deny 90792 with surprising frequency when the note reads like a therapy intake with a medication paragraph bolted on. If the medical element is thin, bill 90791 and schedule the E/M on a separate date. It pays slightly less and gets denied far less.

Standard outpatient counseling is CPT territory on commercial claims and H-code territory on many Medicaid claims, and the two sets are not interchangeable. The CPT psychotherapy family is time-based: 90832 for 30 minutes, 90834 for 45, and 90837 for 60. Time thresholds follow the CPT midpoint convention, so a 53-minute session supports 90837 while a 40-minute session lands on 90834. Family therapy splits into 90846 without the patient present and 90847 with the patient in the room. Group psychotherapy is 90853, billed once per patient per group session. Medicaid substance use programs often route the same clinical work through H0004, individual counseling billed in 15-minute units, and H0005 for group counseling. The unit structure is the trap. H0004 is a unit code: a 60-minute session is four units, not one. Bill it as one unit and you just wrote off 75 percent of the session. Bill a per-session code in multiple units and you triggered an overpayment review. Every biller who has crossed from commercial into Medicaid work has stepped on this rake at least once. Watch modifier requirements too. Many states attach license-level modifiers to H0004 (HF, HN, HO and similar) that change both the payable rate and whether the claim pays at all. A clean crosswalk taped next to the monitor, mapping each clinician's license to the required modifier by payer, prevents more denials at this level of care than any software setting.

Nine hours a week is the line. ASAM Level 2.1, intensive outpatient, means at least nine hours of structured programming weekly for adults, typically delivered in three-hour blocks across three or more days. Cross that threshold with the documentation to prove it, and billing moves from per-session codes to per diem codes. H0015 is the workhorse. It is a per diem: one unit equals one day of IOP programming, whether that day held three hours or four. It began as a Medicaid code but appears on commercial claims constantly, because many commercial plans adopted it rather than invent an alternative. S9475, an ambulatory per diem from the S-code set, is the other code you will meet on commercial IOP and ambulatory detox claims; some national plans prefer it, and their systems reject H0015 outright. Same service, different code. Check the payer's behavioral health billing guide before the first claim goes out, not after the first denial comes back. Facility-side programs billing institutional claims on the UB-04 use revenue code 0906, intensive outpatient for chemical dependency, usually paired with H0015 as the HCPCS on the service line. Whether a given payer wants the professional claim, the institutional claim, or the institutional claim with the HCPCS attached is a contract-level question, and getting it wrong produces the most maddening denial in the specialty: correct patient, correct service, correct code, wrong claim format. Group notes for every program day, attendance records, and weekly hour totals belong in the file. Concurrent reviewers ask for all three.

Step up from IOP and the arithmetic changes again. Partial hospitalization, ASAM Level 2.5, means 20 or more hours of programming per week, delivered during the day while the patient sleeps somewhere else. The defining phrase inside H0035 is under 24 hours: it is a day-treatment per diem for a patient who is not an inpatient. On institutional claims, PHP rides on revenue codes 0912 and 0913, and payer setup determines which one a given contract expects. Commercial plans frequently manage PHP under their inpatient review rules even though the patient goes home at night, which means precertification, an assigned case manager, and concurrent review on a short leash. Authorizations often arrive in three-day to seven-day increments. Miss a review call and the payer stops the clock; the program keeps treating, and the claims for those uncovered days walk straight into a denial. PHP is also where medical necessity documentation has to work hardest. The chart must support why this patient needs 20-plus hours a week rather than the nine of IOP: instability that does not yet require a bed, a failed trial at a lower level of care, psychiatric comorbidity that needs daily monitoring. Reviewers read those notes against ASAM criteria dimension by dimension. Thin notes at this level do not just risk one denied day. They can unravel the entire authorization.

Residential care abandons hourly billing entirely. Everything at ASAM Level 3 and above is a per diem, one unit per day, and the H-code family carries most of it. H2036 is the general treatment program per diem, the code most state Medicaid programs assign to clinically managed residential treatment. H2034 covers the halfway house per diem, the supportive-living end of the residential spectrum where programming hours are lighter and the bed itself is the service. Which residential sublevel (3.1, 3.3, 3.5, or 3.7 in ASAM terms) maps to which code, and at what rate, is defined state by state, and two neighboring states routinely disagree. Detox has its own pair. H0010 is sub-acute detoxification in a residential setting, the medically monitored withdrawal management most freestanding programs provide. H0011 is acute detox, the medically managed level with physician coverage around the clock, closer to a hospital service. The clinical distinction that separates them (monitored versus managed) is exactly the distinction payer reviewers probe, so admission notes need vital sign protocols, CIWA or COWS scores, and documented physician involvement from day one. Commercial plans handle residential inconsistently. Some accept the H-codes. Some require institutional claims with room-and-board revenue codes. Some carve residential out entirely to a behavioral health subcontractor with its own claim address and its own rules. Verify all three questions (code set, claim format, submission address) during the benefits check, while the patient is still in admissions rather than already occupying the bed.

Medication assisted treatment splits along payer and setting lines more sharply than any other service in this guide. Opioid treatment programs dispensing methadone bill Medicare through the bundled G-codes, G2067 through G2080. These are weekly episode bundles: the drug, its administration, and the required counseling are packaged into one weekly payment, with separate codes in the range covering different medications, intake activities, take-home supplies, and add-on counseling. A Medicare OTP claim is short, but the weekly bundle logic has to be exact, because overlapping weeks and duplicate bundles are automatic rejections. Outside Medicare, many Medicaid programs still pay methadone through H0020, the methadone administration code, billed per dose or per day depending on the state. Office-based buprenorphine works differently. There is no bundle. The prescriber bills standard E/M codes (99202 through 99215) for the medical visit, and counseling is billed separately through the psychotherapy or H-code family, depending on who provides it and which payer is on file. Induction visits justify higher-level E/M codes when the note shows the time and the medical decision making; stable maintenance visits usually land at 99213 or 99214. One compliance point catches programs repeatedly: counseling attached to MAT must be documented as a distinct service with its own time and content if it is billed separately. A medication note that mentions ten minutes of supportive conversation does not support a 90832 on the same claim, and payers have grown practiced at spotting that pattern.

None of these codes pay themselves. Substance abuse claims fail at higher rates than almost any other specialty, and the failures cluster around a handful of habits that separate programs with clean receivables from programs writing off entire episodes. Prior authorization first. Nearly every level of care above standard outpatient requires it: IOP, PHP, residential, and detox admissions almost universally. The initial authorization is usually manageable. Concurrent review is where programs bleed. Payers authorize in short blocks and demand updated clinical information to extend them, so a missed review call in week two can void coverage for days already delivered. Someone on staff needs to own the review calendar the way a charge nurse owns the med schedule. Write documentation to ASAM criteria, because that is the rubric reviewers score against. Notes that track the six dimensions (withdrawal risk, medical conditions, emotional and behavioral conditions, readiness, relapse potential, living environment) win appeals. Generic progress notes lose them. Unit math deserves a standing audit. Fifteen-minute codes billed as sessions, per diems billed as hours, group codes billed once per group instead of once per patient: each is a quiet revenue leak that compounds weekly. Telehealth adds one more variable, since coverage for counseling codes delivered by video varies by payer and by state, with separate rules for audio-only in several states. Verify per payer before building a virtual track. The backdrop makes the effort worth it. Initial denial rates hit 11.8 percent across healthcare in 2024 per Kodiak Solutions, behavioral health runs above that average, and Premier's 2024-2025 data shows roughly 70 percent of denials that get fought are ultimately overturned. Appeals work; most programs simply lack the staff hours to file them. Our denial codes reference covers the decoding side of that fight. And if the whole cycle needs stronger hands, our substance abuse billing team works these codes for treatment programs nationwide. A conversation costs nothing, so reach out here.