CIGNA has made its Cost of Care Estimator available to 550,000 doctors, hospitals, and clinics around the nation as a tool to inform patients about their share of the cost of care before they get services, the company said. The itemized, real-time estimates, which are based on a member's specific health plan, explain how the insurance will be applied and what the patient would owe. The information can help avoid financial surprises and may head off potential over-billing by care providers, CIGNA said.