ASHINGTON, April 5 — When Dr. Stephen C. Albrecht of Olympia, Wash., called a hospital in Tacoma recently to inquire about one of his patients, an 18-year-old treated for an infectious disease, he had trouble getting information.

Under a new policy at the Hebrew Home of Greater Washington, a 558-bed nursing home in Rockville, Md., callers can get information about patients only if they have a password or "verification code."

And Dr. Matthew J. Messina, a dentist in Fairview Park, Ohio, near Cleveland, said he had changed the schedule posted each day in his treatment room, so patients would be identified only by their first names.

New federal rules to protect the privacy of medical records take effect on April 14 and the changes have touched off a quiet revolution in the health care industry. Doctors, hospitals, drugstores and other health care providers must limit the disclosure of information about patients.

From big teaching hospitals in New York to tiny clinics in west Texas, much of the industry is preoccupied with the new standards, which will be noticeable to anyone who visits a doctor or a dentist. Providers must now give a written "notice of privacy practices" to every patient, and the notice must be posted in a prominent place in every office, clinic and hospital.

The notices tell patients how their medical information may be used and advise them of their rights, including the right to inspect and copy their records and request corrections. Patients can get copies of doctors' notes, X-rays and laboratory results, as well as data collected on them by their insurance companies.

Rarely have federal rules had such pervasive effects on the health care industry. "It's a new era," said Dr. Spencer Foreman, president of Montefiore Medical Center in the Bronx.

The rules affect not only health care providers but also their "business associates," including answering services and the people who transcribe the notes dictated by doctors after examining patients.

A whole industry of consultants is advising health care providers on how to comply. They sell training manuals, software, security devices and other technology to prevent the improper disclosure of health care information. They highlight the need for their services by noting that violation of the rules is punishable by civil and criminal penalties, including a $250,000 fine and 10 years in prison for the most serious offenses.

"The compliance seminars that I've attended are frightening and at times overwhelming," said Dr. Michael J. Marcello, a family doctor in Mathews, La. "The rules are vast and full of nuances."

But Joy L. Pritts, a privacy expert at Georgetown University, said the federal standards would be "a major beneficial change for consumers in the many states that don't have statutes telling patients how they can get their own medical records."

Federal officials say the new rules should not interfere with the flow of information needed to treat patients and pay claims. But doctors and hospitals, uncertain about what the rules allow, have become much more cautious about sharing or disclosing information.

Dr. Albrecht was surprised when even he had difficulty getting information about his 18-year-old patient.

"The emergency room physician at the hospital in Tacoma would not discuss his care, the X-ray results or the lab studies for my patient, for fear of violating the federal rules," Dr. Albrecht said. "I don't know who was right legally, but I do know that the rules are creating a lot of confusion."

Researchers, journalists and clergy members say hospitals are refusing to provide certain types of information that has been routinely available for many years.

Alicia Mitchell, a spokeswoman for the American Hospital Association, said, "The rules clearly mean that less information will be available to news media and the public."

Scientists are racing to get permission from patients who were unaware that their health information was being routinely used for research without their consent.

Dr. David Korn, senior vice president of the Association of American Medical Colleges, said: "Community hospitals are becoming much less willing to give researchers access to medical information on their patients, including those who were treated 5, 10 or 15 years ago. Some hospitals have concluded that the burden and costs and the threat of liability are not worth it."

The rules, issued under a 1996 law, the Health Insurance Portability and Accountability Act, were written by the Clinton administration and endorsed, with changes, by the Bush administration.

Advocates of the rules cite many cases in which people were harmed or embarrassed by a breach of medical privacy. Workers with H.I.V. or mental illness have lost their jobs. Computer hackers have gained access to treatment records for thousands of patients. Drugstores have shared records with companies marketing prescription drugs.

In general, the rules say, health care providers must limit the disclosure of personal health information to the "minimum necessary" to achieve a given purpose. In practice, that means a multitude of changes.

Many doctors have changed sign-in sheets in their offices, so patients do not have to indicate the reasons for their visits.

Dr. Conrad L. Flick of Raleigh, N.C., said he had removed the names of patients from the outside cover of their charts and installed a glass partition, so staff members could not be overheard as they schedule appointments on the telephone.

Many doctors, like Deborah G. Haynes in Wichita, Kan., have taken a simple precaution to conceal patients' names. When charts are placed in boxes or racks outside examining rooms, nurses make sure the names face the wall.

Elsewhere, doctors and nurses have been told to lower their voices and minimize the use of patients' names in hallway conversations. Many doctors' offices and hospitals have installed privacy screens on computers.

Montefiore Medical Center in the Bronx has put up walls in the reception area where patients are interviewed prior to admission.

Giant Food, which operates more than 100 pharmacies at its grocery stores in the Washington area, has told shoppers to "expect some delays at the pharmacy counter." Under the federal rules, Giant notes, each person filling a prescription will be given a notice of the company's privacy practices and will be asked to sign a form acknowledging receipt.

In a leaflet for customers, Giant says: "You must now pay for all prescriptions and regulated items, such as insulin and needles, in the pharmacy. This procedure keeps your health information from being shared with other store associates, who are not trained in privacy compliance." Until now, Giant customers could pay for prescriptions in the grocery checkout lines.

Many Blue Cross and Blue Shield plans will not discuss claims with the spouse of a subscriber unless the subscriber has signed a form authorizing such discussions.

At Blue Hill Memorial Hospital, on the coast of Maine, Linda O. Abernethy, director of patient care services, said the federal rules made it more difficult to arrange for meals to be delivered to people discharged from the hospital.

"In the old days," she said, "a social worker could pick up the phone and ask Meals on Wheels to deliver lunch to Mrs. Jones five days a week. Under the federal rules, we'll now have to get a release from Mrs. Jones so we can tell Meals on Wheels that, as a diabetic with cardiac problems, she has special dietary needs."

William A. Dombi, vice president of the National Association for Home Care, said the federal rules were changing the culture of home care agencies, making it impossible for nurses to tell patients about the condition of homebound neighbors.

"A visiting nurse can no longer tell Mabel that Gladys, with her broken hip, is walking better than she did last month," Mr. Dombi said. "Those informal communications are no longer allowed."

Under the rules, a hospital can disclose a patient's "condition, described in general terms" — good, fair, serious or critical — but only to callers who ask for the patient by name. If a journalist asks about patients injured in an auto accident but does not know their names, the hospital is not permitted to release any information. Moreover, each patient must be given an opportunity to opt out of the hospital directory. In that case, the hospital will not confirm whether the person is a patient.