What is a health insurance network, and what happens if I go to an out-of-network provider?

A network is the set of doctors, hospitals, and labs that have contracted rates with your insurer. In-network care is billed at those negotiated rates, and your deductible and coinsurance apply as designed. Out-of-network care is often not covered at all under an HMO or EPO, and under a PPO it's covered at a worse rate with a separate, higher deductible.

The bigger risk is balance billing: an out-of-network provider can bill you the difference between their charge and what insurance pays. The federal No Surprises Act protects you from surprise bills in emergencies and from out-of-network providers at in-network facilities, but it doesn't cover care you knowingly choose out of network. Always verify a provider's network status before non-emergency care.