Most routine laboratory tests are unnecessary and should be eliminated, according to research conducted at the University of California at San Francisco.

In a study of 2,000 patients entering a hospital for nonemergency surgery, 60 percent of the tests were ordered as part of the admission routine -- for no specific medical reason. And of those, only four -- or 0.22 percent -- turned up any abnormalities. In none of the four cases did doctors do anything differently as a result of the test.

The researchers estimate that it costs $4,170 for each useful test result.

"In this time of fixed health care appropriations," they write in the Journal of the American Medical Association, "finding a surgically significant abnormality may or may not be worth $4,170, but there may be a better way to spend those dollars to improve health care."

The seven routine tests involved in the study were prothrombin time, partial thromboplastin time, platelet count, complete blood cell count, differential cell count, six-factor automated multiple analysis and glucose level.

Eliminating those tests when there is no reason to suspect a problem could save millions of dollars in U.S. medical costs, the researchers write, arguing that the few lives saved by the tests may not be worth the money.

The cost per life saved by the tests, they estimate, is $4.2 million.