SAN FRANCISCO (CBS SF) — A study of prices for common blood tests in California has discovered patients are subjected to an extreme range of price differences, some charged as little as $10 all the way up to more than $10,000 for the same test.

Researchers at the University of California, San Francisco looked at charges at more than 150 California hospitals and their prices for ten common blood tests that are often required of patients.

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The study found charges for a basic metabolic test ranged from $35 to $7,303, with the median charge being $124.

The price difference for a lipid panel test was found to be the most extreme. While the median charge was $220, the difference ranged from $10 to as much as $10,169, according to researchers.

“You may hear people say that, ‘Charges don’t matter’ or that ‘No one pays full charges,'” said senior author Renee Y. Hsia, MD in a press release. “However, uninsured patients certainly face the full brunt of raw charges, especially if they don’t qualify for charity care discounts,” Hsia said.

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With employers switching to more consumer-directed health plans with higher deductibles and co-pays, out-of-pocket costs for even insured patients can be affected, said Hsia.

Since the blood tests were identical across providers, patients might be expected to think that hospital charges would be similar, according to the statement by UCSF.

“To expect patients to be rational consumers is unrealistic when the system itself is irrational,” Hsia said. “There is very little that we are able to point to that explains the variation, suggesting that the variations are not predictable and therefore a sign of huge inefficiency within the health care pricing system.”

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The report was published Friday in BMJ Open.