''This study shows that health care has equal-opportunity defects,'' said Donald Berwick, who runs the nonprofit Institute for Healthcare Improvement in Cambridge, Mass.

The survey of nearly 7,000 patients, reported today in the New England Journal of Medicine, considered only urban-area dwellers who sought treatment, but it still challenged some stereotypes: The blacks and Latinos actually got slightly better medical treatment than whites.

The researchers acknowledged separate evidence that minorities fare worse in some areas of expensive care and suffer more from some conditions than whites, but they found that once in treatment, minorities' overall care appears similar to that of whites.

''It doesn't matter who you are. It doesn't matter whether you're rich or poor, white or black, insured or uninsured,'' said chief author Steven Asch, at the Rand Health research institute, in Santa Monica, Calif. ''We all get equally mediocre care.''

The researchers examined medical records and phone interviews of 6,712 randomly picked patients who visited a medical office within a two-year period in 12 metropolitan areas from Boston to Miami to Seattle. The group was not nationally representative but does convey a broad picture of the country's health care practices.

The survey examined whether people got the highest standard of treatment for 439 measures ranging across common chronic and acute conditions and disease prevention. It looked at whether they got the right tests, drugs and treatments.

Overall, patients received only 55 percent of recommended steps for top-quality care - and no group did much better or worse than that.

Blacks and Latinos as a group each got 58 percent of the best care, compared with 54 percent for whites. Those with annual household income over $50,000 got 57 percent, 4 points more than people from households of less than $15,000. Patients without insurance got 54 percent of recommended steps, just one point less than those with managed care.

As to gender, women came out slightly ahead with 57 percent, compared with 52 percent for men. Young adults did slightly better than the elderly.

There were narrow snapshots of inequality: An insured white woman, for example, got 57 percent of the best standard of care, while an uninsured black man got just 51 percent.

''Though we are improving, disparities in health care still exist,'' said Garth Graham, director of the U.S. Office of Minority Health.

Graham, who is black, pointed to other data showing enduring inequality in care, including a large federal study last year. He also said minorities go without treatment more often than whites, and such people are missed entirely by this survey.add

Brent James, a Salt Lake City doctor and vice president of medical research for Intermountain Healthcare, has worked on several national committees that have tracked the quality of health care in the U.S. since the mid-1990s.

"A big national debate has sprung up on racial disparities," James said. "This [RAND] study shows that it doesn't matter what subgroup you look at, we screw it up at a pretty constant rate throughout the nation."

He said he believes Utah surpasses the national rate of patients receiving just 55 percent of recommended care.

"It's clearly not that low in Utah," James said. "We have put in systems that have made it easier for our physicians to do it right."

Some of those include making patient records electronic, improving bedside monitoring and developing an antibiotic-assistance program.

"There was a belief among physicians that, given the complexity of medicine, you couldn't do better. We [in Utah] are showing that you can do better," he said.

James also is one of 14 members of the Citizens' Health Care Working Group, charged by Congress with traveling the country to gather ideas for improving U.S. health care, access to insurance and lowering medical costs.endadd

Some experts took heart in the relative equality within the survey. ''The study did find some reassuring things,'' said Tim Carey, who runs a health service research center at the University of North Carolina-Chapel Hill.

Health experts blame the overall poor care on an overburdened, fragmented system that fails to keep close track of patients with an increasing number of multiple conditions. Quality specialists said improvements can come with more public reporting of performance, more uniform training, more computerized checks and more coordination by patients themselves.