Everyone has heard stories about incompetent doctors whose medical licenses were revoked in one state, but who simply moved to another state, got a new license and continued to harm their patients. For years, officials at hospitals, medical societies and state licensing boards have said they were powerless to stop this practice without some national system for sharing information about bad doctors.

Now there is a way. Four years after Congress ordered it created, the National Practitioners Data Bank quietly opened for business last Sept. 1. From that date on, disciplinary actions against doctors and dentists as well as malpractice payments to their patients must be reported to the data bank. Moreover, every hospital is required to check its doctors' records regularly and before granting hospital privileges to a new physician.

After years of wrangling and delay -- while doctors' groups tried to block the data bank and consumer activists complained that its information should be available to the public -- those involved seem surprised that it is finally off and running.

"People are pretty amazed that it actually started," said Lynn Soffer, a doctor formerly with Public Citizen's Health Research Group, who serves as a consumer advocate on a committee advising the data bank. "I think people definitely didn't realize how huge a thing it would be to make it work."

As of Dec. 14, the data bank had received queries about 204,334 doctors, and approximately 15,000 new queries pour in each week, according to Robert Harmon, administrator of the Health Resources and Services Administration within the Department of Health and Human Services (HHS). Employees at Unisys Corp., a Pennsylvania-based contractor that runs the bank for HHS, are struggling to keep up with the requests.

"The hospitals of the land have not held back," said Fitzhugh Mullan, director of HHS's Bureau of Health Professions, which is in charge of the bank.

A total of 4,610 reports of actions taken against practitioners had been received as of Nov. 30, Harmon said. About 80 percent of these were reports of malpractice payments and 20 percent concerned disciplinary actions by medical regulators.

Patients may not query the data bank, and individual doctors are allowed to check only their own records. Hospitals are the only organizations legally required to use the bank, but state licensing boards and medical societies may also do so. In addition, nursing homes, health maintenance organizations and other organizations that conduct formal peer review of practitioners -- such as some large group practices -- are entitled to access.

The data bank was established under a 1986 law and currently covers only physicians and dentists. But a 1987 amendment states that it eventually should be expanded to cover nurses and other health care practitioners.

Mullan said the records on doctors come from four sources. State medical and dental boards are required to report all disciplinary actions taken against a practitioner's license. Professional societies must report any action taken against a member because of professional incompetence or misconduct. Hospitals must report any restriction on a doctor's or dentist's privileges that lasts for longer than a month. And any payment to a patient because of a malpractice claim -- whether it results from a trial or a settlement -- also must be reported.

Doctors' groups like the American Medical Association opposed the data bank's creation, but Mullan said that since it has opened they have been "extremely cooperative."

Harmon said "the only significant issue" has been a lawsuit filed by the American Dental Association to contest a requirement that individual dentists report money refunded to patients who complain about their dental work.

Deciding how to handle the problem of doctors addicted to drugs or alcohol was "a big bone of contention," Soffer said. Doctors' organizations argued that if addicted doctors knew that any treatment for addiction would be reported to the data bank, they would have less incentive to seek rehabilitation.

Under current rules, "if a practitioner voluntarily agrees to go into a rehabilitation program because of activities that were drug- or alcohol-related, that is not required to be reported," Mullan said. If a doctor refuses rehabilitation and is disciplined by a hospital, licensing board or medical society, the action must be reported.

Mullan said that all reports to and from the data bank must be submitted on paper, and officials do not plan to allow "on-line" access because they are worried about computer security. To use the bank, hospitals or other qualified organizations are assigned individual numerical codes.

The question of public access was hotly debated before the data bank was established, and consumer organizations continue to urge that its information be made publicly available.

"We still are pressing very hard to get the law modified," said Sidney M. Wolfe, director of Public Citizen's Health Research Group. He said patients should be able to request reports on their doctors, and doctors should be able to check the data bank's records on other physicians to whom they refer patients.

"If {patients} are brave, they can ask their doctor to see the report," said Soffer, who now works for Group Health Association. She said she plans to post her own report. "I certainly have nothing to hide," she said.

Since the data bank contains no information on anything that happened before last Sept. 1, it will be several years before it provides users with a detailed picture of doctors' and dentists' competence, Mullan said. But, in time, it will make it much harder for incompetent practitioners to hide their histories.