The HHS Office of Inspector General identified at least $77.8 million in improper fee-for-service Medicaid payments made by Colorado for applied behavior analysis services to children, exposing serious gaps in state billing controls, provider verification, and utilization review on a high-volume, high-dollar benefit category.

ABA services for autism spectrum disorder represent one of the fastest-growing Medicaid expenditure categories nationwide. Colorado's case reveals the vulnerability of this growth: insufficient authorization protocols, inadequate provider credentialing, weak billing audit systems, and delayed detection of overpayment. The $77.8 million figure likely represents the OIG's statistical sample projection—actual improper payments across Colorado's ABA spending may be considerably higher. This mirrors patterns from other states: Massachusetts, Texas, and New York have all uncovered major ABA billing fraud and overpayment issues in recent years. The common threads are high service volumes, complex billing codes, limited provider supply (creating licensing and credentialing shortcuts), and autism diagnosis inflation as schools and private payers expanded access.

For billing operations teams, healthcare IT vendors, and compliance officers, this is a critical warning. ABA billing is complex—sessions vary by duration, setting, and clinical complexity, creating numerous opportunities for coding errors or intentional upcoding. States and payers are now implementing tighter documentation requirements, pre-authorization mandates, and post-payment audits. Providers offering ABA should expect increased scrutiny and potential retrospective audits. For Medicaid-heavy practices, this adds pressure to invest in accurate billing infrastructure and clinical documentation. Colorado will likely implement clawback collections, potentially affecting provider networks months or years after services were rendered. Practices with significant ABA revenue should conduct immediate internal billing audits and ensure all provider credentials, authorizations, and claim documentation meet current state standards.

What to watch: Colorado's ABA billing rule changes and clawback collection timeline, expected within Q2 2026, which will set the template for other states' enforcement actions.