I see a little research about this, but the ebola scare is what brought it up for me.
Here in Florida, we do not have ACA or medicaid expansion (like Texas and many red states). Hospitals have often been purchased by for profit companies even though they often retain the original name of a charitable or non-profit organization. We have for-profit hospitals begging for donations under the old name like "children's" or "community" or something that sounds nice. People donate without even realizing that the hospital is paying owners and investors now. There are bill-boards advertising ER's with digital clocks showing "wait time". It's really a commercial enterprise.
When we were raising adopted and foster kids who were covered by medicaid we had one child with a chronic illness. If we went to an ER, there would be tests, referrals, and sometimes admission. Even medicaid paid for specialists and expensive drugs. Once the child was an adult and not covered, all of a sudden a visit to the ER got pain meds and out the door. In fact, the child developed a drug habit that we blamed on ER visits and quick pain prescriptions instead of treatment after the medicaid ran out.
My wife and I are educators and have insurance with union negotiated benefits (thank goodness). Treatment for chronic illness is covered and copays are small or zero. On the few occasions we went to an ER for something that might be scary, we have insurance and they will run tests, call in a specialist, contact the family doctor, and produce meds from the hospital pharmacy. Admission overnight for observation is no problem. We have noticed lately there are lots of bills from consulting doctors in the ER who are out-of-network and that becomes an issue, but we've learned to ask. We are also astounded at the EOB where the insurance pays $30,000 or something for a single visit, but we don't have any control or choice. We just pay the copay (usually a few hundred). We actually heard EMT's one time discussing which ER to go to based on perceived insurance, and I told them the hospital (and they complied). Maybe the ambulance crew gets kickbacks or something?
Students we teach (from kindergarten to college) are often treated similarly. The ones with insurance get tests, referrals, and often admission just in case. We see the difference when college students with loans and minimal insurance are compared to student athletics covered by prime time university group policies. We see the same thing with free-lunch, low income students vs. middle-classers whose parents have family policies. Treatment depends on insurance, not good medical practice.
If you are in a state with minimal medicaid and you are going to a for profit hospital without insurance, unless you are almost dead you'll be given a prescription and referral and tossed out. If you have insurance, including medicaid, you'll be treated with every test and drug. In fact, they will likely milk the insurance for whatever they can get away with...so you may have to be assertive to stop them. (That's how Rick Scott got rich over-billing medicare for fake treatments.).
The FOR PROFIT system doesn't work, because the incentive is to ignore the uninsured (even if they have ebola) and overcharge the insured who really don't have a chance to shop around or argue with the doctor. The good thing about ACA is they are trying to collect data and hold the hospitals to reasonable costs. Maybe in the long run that will work, but it will be a fight against a motivated and unethical corporate industry.
We need a public, single-payer system or else health care needs universal non-profit insurance (like they have in some places in Europe). Otherwise, there will continue to be abuse.