IL SB1658

Defines "facility-based providers" as physicians or providers offering radiology, anesthesiology, pathology, neonatology, or emergency department services in participating hospitals or ambulatory surgical centers.

Requires insurers to limit out-of-pocket costs for beneficiaries using nonparticipating facility-based providers when in-network services are unavailable to the same amount they would pay with participating providers.

Allows beneficiaries to assign insurance benefits to nonparticipating providers in writing, with the provider receiving direct payment from the insurer and billing the patient only applicable deductibles, copayments, or coinsurance amounts.

Establishes a binding arbitration process through the Department of Insurance to resolve payment disputes between insurers and nonparticipating providers if negotiations fail within 30 days, with arbitration decisions issued within 45 days.

Exempts the provision from applying when beneficiaries willfully choose nonparticipating providers when network alternatives are available, and preserves prudent layperson standards for emergency services.