Next here tonight, "world news" investigates outrageous hospital costs, those expensive and wildly confusing bills. We have been reading so many of your stories, the ones you have sent to us. Tonight... See More
Next here tonight, "world news" investigates outrageous hospital costs, those expensive and wildly confusing bills. We have been reading so many of your stories, the ones you have sent to us. Tonight the story of two different places, an identical set of tests and one place charging the patient so much more. Why? Abc's rebecca jarvis, the "world news" investigation critical condition. Reporter: An outpouring. 52,000. Reporter: Hundreds of you sending us your stories of outrageous hospital bills. What can be done? Reporter: Kathy meinhardt has her own store. She understands buisiness, because she runs one out of her home in northern california. But what she can't understand are the two bills she received after some blood work. It was outrageous. What was outrageous about it? The cost difference. Reporter: For the exact same tests performed within a couple hundred feet of each other. First she came here to quest diagnostics, then went up the street to a hospital just down the block. We timed it. Two locations, just a minute away. And for the same ten tests the hospital's outpatient lab charges 2.5 times quest's price. But if you look at what kathy was asked to pay out of pocket, it's seven times as much. Nearly $2,000 at the hospital. And less than $300 at quest. Yes, a block apart, both in her insurer's network. Why would I think that the prices would be so dramatically different from one lab that is right across the street. It's highway robbery. Reporter: We asked the hospital for an on camera interview. Instead they provided this statement. "Comparing a hospital with a free standing facility is an apples to oranges comparison." So we went to the california hospital association to ask why prices are so high. Reporter: Rebecca jarvis, abc news. Is that a fair price? I will just say to you it is the price. You can't tell me it's a fair price? I will tell you it is a fair price when you look at all the complexities of what goes on a bill. Reporter: The industry calls it cost shifting. People like kathy pay more to cover those who pay nothing. Hospitals also have higher overhead, but none of that is ever explained anywhere on your bill. Each individual hospital sets its own pricing formula. And how do they come up with that formula? Every hospital does it differently. But what goes into that formula? Every hospital chooses to do that differently. You might want to call a hospital or two and ask them about that. They sent us to you. Reporter: With so many hospitals, doctors, labs and insurance companies negotiating rates confidentially among themselves, patients are at their wits end. It's part of a complex, hospital finance discussion. And I wouldn't expect any lay person to ever understand any of this. But shouldn't all this be crystal clear to the lay person? It's unfortunately very complex. Reporter: It's a mess. In kathy's case the hospital and her insurance company after more than a year reached an agreement on a lower price. But I want to remind everybody, that's what you need to do. You need to ask for an itemized bill and challenge the things that just don't make sense. Diane, we're going to keep on this. We have solutions right now at abcnews.Com. People can challenge them and start negotiating. Negotiate them down, okay, as you said you'll stay on this case. Send us your stories on our facebook page. Next right here,
This transcript has been automatically generated and may not be 100% accurate.