Only part of what I said refers to emergency care. MediCal and its state law equivalents (called QUEST in Hawaii) and the numerous community clinics do permit preventive healthcare. We already have a safety net. Universal Healthcare might lower some costs, but will significantly increase others.
But we'll find out just how much the government will sock it to all of us if President Hillary takes over. 
The only federally mandated healthcare I am aware of is emergency healthcare.
I looked up Med-Quest for hawaii but I can't find the particulars.
States can set up whatever system they like but there is no federal safety net.
What other costs will increase with UHC?
Right now employer provided HC is disappearing. Profit motive of insurance companies greatly contribute to that. Government is infinitely more economical in replacing insurance companies in some aspects--look at SS compared to private insurers re coverage and administrative costs.
When you don't have to fund to pay for corporate jets, golden parachutes, executive comp, the savings add up.