Why 97153 and 97155 Concurrent Denials Are Draining ABA Revenue Right Now

Across the roughly 50 behavioral health and ABA practices we work with at Revenant Care Group, one denial pattern has become impossible to ignore heading into 2026: payers are systematically rejecting claims where 97153 (Adaptive Behavior Treatment by Protocol) and 97155 (Adaptive Behavior Treatment with Protocol Modification) are billed on the same date of service, same beneficiary, same rendering provider group. We are not talking about edge-case denials. We are talking about denial rates hitting 35 to 55 percent on concurrent-service claim lines at mid-size ABA practices billing 200 to 400 units per week. At an average allowed rate of $12 to $18 per 15-minute unit depending on payer and state, that exposure compounds fast.

The frustrating part is that these services, when properly documented and staffed, are clinically and procedurally legitimate. The concurrent model is how ABA is supposed to work: a Registered Behavior Technician (RBT) delivers direct treatment under CPT 97153 while a Board Certified Behavior Analyst (BCBA) simultaneously supervises and modifies the protocol under CPT 97155. Payers know this. Their own clinical policy bulletins acknowledge it. The denials are not happening because the services are wrong. They are happening because of modifier misuse, POS inconsistencies, and supervision documentation gaps that automated claims adjudication systems flag before a human ever looks at the chart.

The Specific Modifier Errors We See Most Often

The single most common technical reason we see for concurrent 97153 and 97155 denials is missing or incorrect use of the HO, HM, and HN modifiers combined with failure to append the HA modifier when a payer specifically requires it to identify the supervising BCBA’s credential level. Here is how the staffing modifier logic is supposed to work for most commercial and Medicaid managed care payers in 2026:

• 97153 billed by the RBT should carry the HM modifier (less than master’s degree level) in most payer contexts, though some payers require HN (bachelor’s degree level) depending on state licensure frameworks.
• 97155 billed by the BCBA should carry the HO modifier (master’s degree level or above) to identify the supervising clinician’s credential tier.
• When both codes appear on the same claim for the same DOS, many payers require a concurrent modifier indicator, and some Medicaid programs have added a specific modifier or revenue code requirement that is not consistently communicated in provider manuals. We pull those payer-specific requirements manually for every payer contract we manage.

Beyond staffing modifiers, we consistently see claims submitted under POS 11 (Office) when services were delivered in a POS 12 (Home) or POS 99 (Other Unlisted) setting. POS mismatches on concurrent claims trigger automatic denials with remark code CO-4 or CO-16 at a disproportionately high rate because the payer’s system interprets the concurrent-service flag and the POS inconsistency together as a credibility failure.

What “Same Rendering Provider” Rules Are Actually Saying

One of the most misunderstood denial triggers in concurrent ABA billing is the payer’s same-rendering-provider edit. When 97153 and 97155 are billed under the same individual NPI rather than correctly split between the RBT’s supervising NPI and the BCBA’s individual NPI (or the group NPI with appropriate taxonomy), payers treat it as a duplicate service edit, not a staffing model edit. The result is an automatic CO-97 denial (payment included in allowance for another service) or an OA-18 (duplicate claim).

The fix requires your billing team to confirm that your practice management system is configured to submit 97155 under the BCBA’s individual NPI as the rendering provider, and 97153 under the RBT’s supervising structure as the billing arrangement your payer contract specifies. This is not a clinical documentation problem. It is a credentialing and system-configuration problem, and it takes about two to four hours to audit and correct per payer contract. The downstream revenue recovery for a practice billing 300 units per week at a 40 percent concurrent denial rate averages $18,000 to $28,000 in recovered monthly revenue once corrected, based on what we are actually recovering for practices in that size range.

Documentation Requirements That Payers Are Now Auditing on Appeal

Even when modifiers and NPI configuration are correct, concurrent 97153 and 97155 claims are increasingly being pulled into post-payment audits by commercial payers in 2026. What they are looking for on appeal is very specific. Your clinical documentation needs to show:

• The BCBA’s session note for 97155 must document the specific protocol modification made during that session, not a standing treatment plan reference. Phrases like “continued current programming” are being used to deny 97155 as not medically necessary on appeal.
• The time overlap between 97153 and 97155 must be explicitly documented, meaning both the RBT’s session time and the BCBA’s direct supervision time must appear in the record with start and stop times that confirm genuine concurrency, not sequential service delivery.
• Supervision ratios must match your payer contract. If your contract specifies a 1:3 BCBA-to-RBT supervision ratio maximum and your session notes show one BCBA concurrently supervising four RBTs, every 97155 unit billed that day is at risk.

If you are facing parity-based denials layered on top of these technical edits, the appeals strategy is different. We have covered how to use MHPAEA leverage in behavioral health denial appeals in detail at our mental health parity appeals resource, and the same framework applies when payers apply medical necessity criteria to ABA that they would not apply to comparable habilitative services.

The Appeals Process That Is Actually Recovering Revenue

For practices already sitting on a backlog of denied concurrent claims, the recovery process is procedural and time-sensitive. Most commercial payers have a 180-day timely filing limit on first-level appeals. Medicaid programs vary by state, but 90 days from the denial date is a common hard cutoff. Here is the appeals structure we are using successfully for concurrent 97153 and 97155 denials in 2026:

• Level 1 appeal: Correct the modifier and NPI configuration errors, resubmit as a corrected claim (condition code D1 on institutional claims, or CMS-1500 Box 22 with resubmission code 7) within the payer’s correction window before triggering a formal appeal.
• Level 2 appeal: If corrected claim denies, file a formal first-level appeal with the concurrent supervision policy from the payer’s own clinical policy bulletin attached as Exhibit A, alongside the BCBA’s session notes showing protocol modification specificity.
• Level 3 appeal / External Review: For claims above $500 in allowed amount per date of service, external independent review organizations (IROs) are overturning concurrent ABA denials at a rate we estimate above 60 percent when documentation is clean, based on outcomes we are tracking across our current client portfolio.

For a 20-clinician ABA practice, a 90-day backlog of concurrent denials at an average denial value of $180 per claim date can represent $90,000 to $150,000 in recoverable revenue. That number is not hypothetical. It is the range we are working through right now with practices in that staffing tier.

How to Audit Your Own Concurrent Claim Exposure This Week

You do not need a full RCM overhaul to identify your exposure. Pull an aging denial report filtered to CPT codes 97153 and 97155 with the same DOS and same client ID. Sort by denial reason code. If CO-97, CO-4, CO-16, or OA-18 appear more than twice in the top 20 results, your configuration and modifier stack has a systematic error, not a one-off problem. Cross-reference your payer contracts for concurrent-service language, then compare that language to what your PM system is actually submitting. If those two things do not match, you found the leak.

This kind of denial pattern analysis is exactly what we do in the first 30 days for every practice that comes to Revenant Care Group. It is also worth noting that ABA practices frequently have layered coding vulnerabilities across service lines. If you are running a multi-service behavioral health practice, the same audit discipline applies to SUD-adjacent coding, and if you are billing drug screening alongside behavioral services, our analysis of G0480 through G0483 under-coding patterns is directly relevant to how payers are auditing bundled behavioral health claims.

Get a Free 30-Day Denial Audit for Your ABA Practice

If your practice is billing 97153 and 97155 concurrently and your denial rate on those claim lines is above 15 percent, you have a recoverable revenue problem that a systematic audit can quantify within the first two weeks. At Revenant Care Group, we offer a free 30-day denial audit specifically for ABA and behavioral health practices where we identify your top five denial drivers, calculate your dollar exposure, and give you a prioritized remediation plan before you spend a dollar on ongoing services. Book a time directly on our calendar here and we will get your denial pattern in front of our ABA billing team within 48 hours.