How is "co-payment" defined in health insurance terms?

In health insurance, "co-payment" refers to a specific, fixed amount that the insured is required to pay for certain medical services at the time they receive care. This is an out-of-pocket expense that is typically outlined in the health insurance policy and applies to various services, such as doctor visits, prescriptions, or emergency care. Co-payments are designed to share the cost of healthcare between the insurer and the insured, making it clear how much individuals need to pay upfront when they seek medical attention.

For example, if a policy specifies a $30 co-payment for a doctor's visit, the insured pays this exact amount at the time of the appointment, and the insurance covers the remaining costs. This differs from an insurer paying a fixed amount or a percentage of a bill, which is not what constitutes a co-payment.