Many insurance policies also require policyholders to pay a certain portion of medical costs that exceed the deductible. This extra amount is called the coinsurance figure. For example, consider a person who has already paid her policy’s deductible for the year and then has a diagnostic test that costs $100. If that person’s health insurance policy sets the terms of coinsurance at 20 percent, the insurance company must pay $80 of the bill for the test and the policyholder must pay $20. Policies that do not require a coinsurance payment usually charge subscribers a relatively high premium.