What is "coinsurance" in health insurance?

Coinsurance in health insurance refers to the percentage of costs that the insured is responsible for after they have met their deductible. For instance, if a plan includes a coinsurance rate of 20%, and a healthcare service costs $1,000, once the insured has satisfied their deductible, they would pay $200 (20% of $1,000) while the insurance company covers the remaining $800. This arrangement is designed to share costs between the insured and the insurer, encouraging responsible use of healthcare services.

The other options represent different concepts within health insurance. The fixed amount the insured pays for each service pertains to copayments, not coinsurance. The total amount that the insurer covers for a year relates to policy limits but does not define coinsurance. A flat fee for policy underwriting is associated with the administrative aspect of insurance and not the sharing of costs after a deductible. Thus, the definition accurately captures the essence of what coinsurance entails in health insurance policies.