ABA Therapy Billing Cheat Sheet (2026)

ABA billing is unit and authorization heavy, and most denials trace to one of three things: units that do not match documented time, the wrong provider type rendering a code, and treatment delivered beyond the authorized amount.

AAPC-Certified
2026 Medicare Fee Schedule
8 Codes Priced

Quick reference for aba therapy billers. Last updated .

Top ABA Therapy CPT Codes & 2026 Medicare Allowables

CodeDescriptionNon-FacilityFacilityTotal RVU
97151Behavior identification assessmentn/an/a0.00
97152Behavior identification supporting assessmentn/an/a0.00
97153Adaptive behavior treatment by protocol, per 15 minutesn/an/a0.00
97154Group adaptive behavior treatment by protocoln/an/a0.00
97155Adaptive behavior treatment with protocol modificationn/an/a0.00
97156Family adaptive behavior treatment guidancen/an/a0.00
97157Multiple-family group adaptive behavior treatment guidancen/an/a0.00
97158Group adaptive behavior treatment with protocol modificationn/an/a0.00

National 2026 Medicare Physician Fee Schedule estimates (total RVU multiplied by the conversion factor). These are adjusted by state locality. See the per-state table on the ABA Therapy billing services page.

Modifiers That Prevent ABA Therapy Denials

HM, HN, HO

Provider education level designators (paraprofessional, bachelor, master) that many Medicaid and MCO plans require to set the rate for the rendered code.

HA or HB

Child or adult program designators where the payer differentiates the benefit.

59 or XP

Distinct services on the same day, such as direct treatment separate from a supervision or guidance code, where the payer would otherwise bundle.

U1 to U9

State Medicaid level or location designators required on ABA claims in many states.

GA

An ABN or equivalent is on file for service beyond the authorized amount, preserving billing of the patient where allowed.

TS

Follow-up service where the payer distinguishes it for supervision or reassessment.

Top ABA Therapy Denials → Quick Fix

Units do not match documented timeCO-16

97153 and the treatment codes are 15-minute units. Document session start and stop times; the billed units have to equal the documented time.

Code rendered by the wrong provider typeCO-185

Match the rendering provider and the modifier to who delivered the service. A protocol-modification code (97155) is not the same as protocol delivery (97153) and not interchangeable by provider.

Treatment beyond the authorized amountCO-197

Track authorized units against delivered units. Reauthorize before the authorization is exhausted; ABA payers rarely pay retroactively for over-cap delivery.

Assessment billed without the authorizationCO-197

97151 behavior identification assessment usually requires its own prior authorization separate from treatment. Obtain and document it before the assessment.

Supervision and direct treatment overlapCO-97

When supervision (97155) overlaps direct treatment, follow the payer's concurrent-billing rule and document the distinct activities; undocumented overlap is denied.

NCCI Bundling Watch-Outs

Code pairs from this specialty's set that carry NCCI edits. Billing both without a justified modifier triggers a bundling denial.

CodeBundles WithRationale
971510403TMisuse of Column Two code with Column One code
971510488TMisuse of Column Two code with Column One code
971520403TMisuse of Column Two code with Column One code
971520488TMisuse of Column Two code with Column One code
971530403TMisuse of Column Two code with Column One code
971530488TMisuse of Column Two code with Column One code
971540403TMisuse of Column Two code with Column One code
971540488TMisuse of Column Two code with Column One code

Documentation That Holds Up on Appeal

Adaptive behavior treatment (97153 to 97158)

Session start and stop times, since every treatment code is a 15-minute unit.

Rendering provider

Who delivered the service and their credential, supporting the code and the level modifier.

Assessment (97151, 97152)

The separate authorization for assessment and the assessment activities and time.

Supervision (97155)

The protocol modification activity and how it relates to concurrent direct treatment.

Authorization tracking

Authorized units versus delivered units, with reauthorization before the cap is reached.

Revenue ABA Therapy Practices Leave on the Table

$

Billing unit counts the session times do not support, which is clawed back on audit.

$

Delivering treatment past the authorization and absorbing the over-cap units.

$

Coding supervision and direct treatment without documenting the distinct activities, so the overlap denies.

$

Performing an assessment without its separate authorization and losing the assessment revenue.

ABA Therapy Billing FAQ

How are ABA treatment units calculated?

Most treatment codes, including 97153, are 15-minute units. Session start and stop times have to be documented, and the billed units must equal the documented time. Rounding up beyond the time fails on audit.

Why do ABA claims deny for the rendering provider?

Because the code and modifier did not match who delivered the service. Protocol delivery (97153), protocol modification (97155), and guidance (97156) are different services with different qualified renderers.

How do we avoid over-cap denials?

Track authorized units against delivered units continuously and reauthorize before the authorization is exhausted. ABA payers rarely pay retroactively for treatment beyond the cap.

Does the assessment need its own authorization?

Usually yes. The behavior identification assessment (97151) typically requires a prior authorization separate from the treatment authorization, obtained and documented before the assessment.

Stop Losing ABA Therapy Revenue to Preventable Denials

Our AAPC-certified aba therapy coders apply every rule on this sheet to your claims. Call 888-701-6090 for a free billing assessment.