ABA Therapy denial code (Updated for 2026)

Common Causes for CO B13

Denials with code CO B13 typically happen for the following specific reasons:

• The payer's system incorrectly categorizes standard ABA CPT codes (97151-97158) as experimental or investigational for the patient's specific diagnosis.
• The patient has a non-Autism Spectrum Disorder (ASD) diagnosis code billed as primary, which triggers plan-specific exclusions that only permit treatment within clinical trials.
• Lack of a valid prior authorization on file that establishes the medical necessity of the ABA therapy as standard care rather than an investigational study.
• Incorrect utilization of temporary or local billing codes instead of the standardized Category I CPT codes established by the AMA.

How to Prevent CO B13 Denials

To avoid receiving this denial in the future, implement these specific checks:

• Conduct exhaustive pre-benefit verifications to confirm that the patient's specific plan covers ABA therapy as an established medical benefit rather than an experimental service.
• Always secure a formal prior authorization before initiating ABA services, ensuring the authorization matches the exact CPT codes (97151-97158) and ICD-10 diagnosis codes.
• Ensure the primary diagnosis code on the claim is a recognized Autism Spectrum Disorder (such as ICD-10 F84.0) to satisfy standard medical necessity guidelines.
• Submit comprehensive clinical documentation, including the initial behavioral assessment and individualized treatment plan, with the initial claim if required by the payer.

Appeal Letter Template for CO B13

If you believe this claim was denied incorrectly, you can use the following template to submit an appeal.

[Your Practice Header]
[Date]

[Payer Name]
[Appeals Department Address]

RE: Appeal for Claim [Claim Number]
Patient: [Patient Name]
ID: [Patient ID]
Date of Service: [Date]
Denial Code: CO B13 - ABA Therapy denial code

Dear Appeals Department,

I am writing to appeal the denial of the above-referenced claim, which was denied with code CO B13: "ABA Therapy denial code".

We are appealing the denial of CPT code(s) [Insert CPT Code, e.g., 97153] for claim number [Insert Claim Number], which was denied under code CO B13. Applied Behavior Analysis (ABA) therapy is not an experimental or clinical trial procedure; it is widely recognized by the American Medical Association (AMA), the American Academy of Pediatrics, and the US Surgeon General as an established, medically necessary treatment for Autism Spectrum Disorder (ASD). In 2019, the AMA transitioned adaptive behavior services to Category I CPT codes (97151–97158), cementing ABA as standard-of-care medical practice. The attached clinical documentation, including the patient's diagnostic evaluation for ASD (ICD-10 [Insert Diagnosis Code]) and individualized treatment plan, clearly demonstrates the medical necessity of these services. We request that the experimental designation be removed and this claim be reprocessed for immediate payment.

Attached please find:
1. A copy of the original claim.
2. The relevant medical records supporting the service.
3. [Any other supporting documents].

We respectfully request that you reprocess this claim for payment.

Sincerely,

[Your Name]
[Title]
[Practice Name]