Should your doctor ask you to make a donation to help the medical center where you were treated? If you are a generous donor, should you be rewarded with a better room — or your doctor’s cellphone number?

Medical centers across the United States are asking patients, especially wealthy ones, to donate money, in addition to whatever they pay for actual care. The money is needed, the providers say, to defray costs or provide charity care.

Despite rigid privacy rules regarding medical records, hospital fund-raising offices are allowed to look at patient’s finances to see if he or she might be wealthy enough to make a significant donation. Ethical guidelines from professional societies say these practices are acceptable.

Until now, no one has asked patients themselves what they think about these increasingly common tactics. A new national survey, published on Tuesday in JAMA, finds that most patients are repelled by these solicitations.

“This is the first study, to my knowledge, reporting what members of the lay public think,” said Dr. Joseph Carrese, a professor of medicine at Johns Hopkins Berman Institute of Bioethics.

Dr. Reshma Jagsi, an ethicist and radiation oncologist at the University of Michigan and lead author of the survey, said she was worried about striking the right balance between the need for funds and the risk of alienating patients.

“We know how important philanthropic funds are to the institutions where we work,” she said. “Yet we have a discomfort that is natural, especially in the context of that sacred patient-physician relationship.”

Some patients do appreciate an opportunity to donate and to show their gratitude to their doctors and the medical institution where they received care, she said.

Dr. Jagsi began probing these questions five years ago with a survey of cancer specialists. Nearly half had been taught to identify wealthy patients, she found, and a third said they had been asked to solicit donations directly from patients. Some 3 percent said they had been promised payments if a patient donated.

To Dr. Jagsi’s surprise, no one followed up with a survey of patients and the general public. So she decided to do it.

The new survey involved a representative sample of the United States population and three other groups: wealthy people, cancer patients and patients with heart disease.

The responses were generally the same among all the groups. But the wealthy patients were slightly more likely to find it acceptable for big donors to get special treatment in return for their contributions.

Asked if they approved of doctors directly asking patients to donate when the patients had not brought it up, 85.8 percent of the general public disapproved, as did 80.5 of people with incomes above $250,000, 85.5 percent of cancer patients and 88.9 percent of heart patients.

Asked if it was permissible for doctors to give patients’ names to the hospital’s fund-raising office without permission, 91.5 percent of the general public said no, as did 89.1 percent of wealthy people, 93.7 percent of cancer patients and 94 percent of heart patients.

Respondents almost universally disapproved of allowing fund-raising offices to check the value of patients’ homes or to review other available information to find out which patients were wealthy.

Ethicists said they were not surprised by the survey’s results. There is a long history of abuses of the doctor-patient relationship, including bribes, kickbacks, self-referrals and charitable contributions, noted Dr. Jonathan Moreno, an ethicist at the University of Pennsylvania.

Fund-raising that crosses ethical lines is unacceptable, he added, and not so different. Even Hippocrates worried about these issues, advising doctors not to give special treatment to the wealthy and to provide care without compensation to patients who had little money.

But current practices at many medical centers are hard to justify, he added.

“Absent evidence that soliciting patients with financial means makes much difference to an institution’s financial viability, and in an era of rampant mistrust, it’s best to forgo such practices,” Dr. Moreno said.

But donations are important to medical centers, said Dr. Marschall Runge, dean of the University of Michigan Medical School and chief executive of its health system. Donations to the university medical center, for example, help defray costs for patients without insurance who are transported by helicopter for urgent care.

Yet Dr. Runge recognized the potential for conflicts between the medical system’s need for money and its obligations to treat patients in the most ethical and honest way.

Dr. Jagsi has helped Dr. Runge and others in the hospital’s administration formulate policies that prohibit doctors from directly asking patients to donate.

“If a patient says, ‘Gee, I’d like to help. Is there anything I can do?,’ the doctor would approach the development office,” Dr. Runge said. “But development will never approach a patient without the physician’s consent.”

The medical center also does not give big donors special privileges, although that is a common practice elsewhere, Dr. Runge said.

“Believe me, I get those discussions not infrequently,” he said. “They say, ‘If I give a big gift, can I get X?’ I say, ‘No, there is no connection.’”

The university is trying to find the best ways of encouraging philanthropy without offending patients. The missing link, Dr. Runge said, has always been knowing what patients think of various fund-raising practices.

Now, following the new research, Dr. Runge will be forming a committee to decide what to do with the findings: “I can promise you we will make changes based on results of that study.”