Discuss PGroot's answer to: How does health insurance work in the US?

As of 2012, medical insurance is not required in the US.  Most employers offer it at group rates, and colleges offer it to students, and most citizens over 65 who have worked are covered by Medicare.  Those with pre-existing conditions like cancer or diabetes pay much higher rates for individual coverage.  Poor people may be covered by Medicaid.  Medical insurance will be required under Obamacare but not this year.  Most medical insurance covers a large fraction (like 80%) of cost, but the patient pays the remainder (20%).  Operations may require advance approval.  If there are cheaper options, the insurance company may refuse a more expensive treatment.