This is a beneficiary cost-sharing mechanism usually in the form of fixed amounts for charges from physicians, hospitals, pharmacies or other healthcare service providers. It is another way of sharing medical costs. In short, it is a form of sharing medical costs under a healthcare insurance plan that requires an insured person to pay a fixed amount when a medical service is received. The insurer (or insurance company) is responsible for the rest of the reimbursement. There may be separate co-payments for different services. Some plans require that a deductible first be met for some specific services before a co-payment applies. Co-payment is a pre-determined, flat fee, in addition to what health insurance covers, paid by the policyholder for availing healthcare services under the plan. Co-payments are not usually specified by percentages.