Co-insurance is a form of medical cost sharing that requires an insured person to pay a stated percentage of medical expenses after the deductible has been met.
A deductible is a fixed dollar amount during the benefit period that an insured person pays before the insurance company starts to make payments for covered medical services.
A co-payment is a per-person, per-visit amount that you are expected to pay before your insurance company begins covering the cost of your care. The provider of care is directed by the insurance company to collect the co-payment from the patient prior to treatment.