This is a form of cost sharing and involves patients paying a percentage of the cost instead of a fixed
sum. For example, if your co-insurance is 25% and a $200 doctor’s visit is approved by Medicare, you pay $50 and the plan covers the other $150. Depending on the plan, you may not pay any coinsurance until the deductible has been covered.
Peter agreed to a co-insurance of 20%, so when his doctor’s visit cost $150, he paid $30 and his health plan covered the remaining $120.