In a PPO (Preferred Provider Organization) plan, what happens if the insured uses an out-of-network provider?

PPO (Preferred Provider Organization) OUT-OF-NETWORK: PPOs offer FLEXIBILITY — the insured CAN use out-of-network providers, but at a HIGHER out-of-pocket cost. IN-NETWORK: Lower cost (negotiated rates, lower coinsurance/deductible); OUT-OF-NETWORK: Still covered, but the insured pays more (higher coinsurance, possibly a separate higher deductible, and may owe the difference between the provider's charge and the plan's allowed amount — 'balance billing'); NO PCP/REFERRAL REQUIRED: Unlike HMOs, PPOs typically don't require a primary care physician or referrals to see specialists; HIGHER PREMIUMS: PPOs generally cost more than HMOs in exchange for flexibility; PPO ADVANTAGES: Freedom to choose providers, see specialists directly, and get some coverage out-of-network; PPO is a major managed care plan type; understanding that PPOs allow out-of-network care at higher cost (and don't require PCP/referrals) — distinguishing them from HMOs — is key health insurance exam content.