MI HB4604

Requires health insurance plans and HMOs in Michigan to provide coverage for diagnosis and treatment of autism spectrum disorders (autistic disorder, Asperger's disorder, and pervasive developmental disorder not otherwise specified).

Prohibits insurers and HMOs from denying, terminating, or refusing to renew coverage solely because an individual is diagnosed with or has received treatment for autism spectrum disorder.

Eliminates visit limits for autism services providers and prohibits dollar limits, copays, deductibles, or coinsurance that do not apply to physical illness, except applied behavior analysis is limited to a maximum annual benefit of $50,000.

Defines covered treatment as evidence-based care including habilitative or rehabilitative care, pharmacy care, psychiatric care, psychological care, and therapeutic care prescribed by a licensed physician or psychologist as medically necessary.

Allows insurers to request treatment reviews and require treatment plans at the insurer's cost, using evidence-based care and managed care cost-containment practices; effective 180 days after enactment for all policies issued or renewed in Michigan.