When the patient pays 500 dollars to receive insurance he is paying an insurance premium.
A premium in finance is the payment a customer has to provide to the seller for the right of service. In our case, insurance companies have different kinds of premiums according to each one of their insurance plans. An insurance premium is paid to have an insurance plan, they can be paid annually or monthly. It is a fixed payment agreed from the start of the deal and you cand receive better benefits after a while because insurance programs value costumers' loyalty by providing them better plans for the same plan for the same amount of money. For example, a life insurance I know provides a death compensation for 500 thousand dollars in the first five years and after that, it doubles.
all the above is what i would say