When Dorothy Gregan's husband picked up her prescription at an Arlington drugstore on Glebe Road, he assumed that it was the medication the doctor had ordered to combat her pneumonia. Instead, for three days she took someone else's medication for peptic ulcers and diarrhea.

Months later, Arlington pharmacist Mike Jenkins, saying that a normally reliable technician had switched labels on two prescriptions, admitted that he failed to check Gregan's prescription and agreed to a fine of $200 by the Virginia Board of Pharmacy.

The fine was one of almost 500 disciplinary actions pushed through by Virginia's 10 health regulatory boards in the past fiscal year, more than 2 1/2 times the number of actions taken the previous year, according to board officials.

Cases ranged from a rural surgeon who allegedly performed numerous unnecessary operations over a period of years to doctors accused of sexual misconduct and nurses found diverting drugs from patients for their own use.

Of the 488 health practitioners disciplined, 32 had their licenses revoked, 51 were suspended, 26 voluntarily surrendered licenses, and 116 could still practice under probation with certain conditions. The rest received lesser disciplines, such as fines or reprimands.

The increased number of disciplines indicates a heightened awareness in recent years regarding medical malpractice, prompted in part in Virginia by state studies in 1982 and 1984 that showed serious flaws in the state's oversight system. And, despite an improved showing, state officials agree that there is still room for improvement.

"We are about a quarter to one-third of the way to where we would like to be," said Bernard L. Henderson Jr., who since January 1986 has been director of the Virginia Department of Health Regulatory Boards, the umbrella agency over the 10 boards that regulate health professionals.

A remaining weak point, according to board officials, is getting doctors and other health professionals to report apparent incompetence by colleagues.

"One of the biggest frustrations we have is that a code of silence still exists among professionals," Henderson said. "We are trying to knock that down."

A review of a number of cases also shows how doctors and other professionals can escape the notice of the boards for years and how, once discovered, it can sometimes take years to complete proceedings against them.

In one sense, the boards suffered from the success of new administrative and legislative efforts to cope with problem doctors. While the boards nearly tripled the number of cases they closed in the past year, the complaints were coming in so fast that the backlog rose slightly, the latest figures show.

In fiscal 1986, the boards received 750 complaints, closed 369 cases and ended the year with a backlog of 796. In fiscal 1987, which ended June 30, they received 1,041 complaints, closed 1,030 cases and still had 807 active cases at the end of the period. Complaints were filed against less than 1 percent of the state's health care professionals.

Henderson attributed much of the increase in new cases to the new hospital reporting requirements, but he said consumers also are bringing more complaints to the boards. The board's figures show about half the complaints coming from consumers last year.

Examples of cases the boards have dealt with in recent years, contained in board files in Richmond, include:From 1979 to 1981, a surgeon in Grundy, Va., performed several unjustified hysterectomies, botched deliveries and unnecessarily circumcised a 15-year-old youth, the Board of Medicine alleged. The surgeon, Dr. Faiq A. Masri, denied doing anything improper. He agreed with the board to let his license expire last year, and the board dropped the case. Masri is practicing in Kentucky. A McLean dermatologist, Dr. David I. Kabir, agreed to be put on probation in 1982 after the board considered allegations brought by two fathers that the doctor had made sexual advances to their teen-age daughters -- one in 1975 and one in 1978. The license was revoked last year when the board, which never resolved the original complaints, found that Kabir among other things had not completed a psychiatric evaluation that he had agreed to undergo.

Kabir has denied the teen-agers' fathers' allegations, according to his attorney, and he has appealed the disciplinary action in Alexandria Circuit Court. After the board reviewed allegations that he improperly managed labor and delivery for 15 women at Alexandria Hospital starting in 1981, Dr. Ludovic J. DeVocht agreed in 1985 that he be placed on indefinite probation and be prohibited from providing obstetrical care to women in their third trimester of pregnancy.

DeVocht's attorney said the doctor had not mismanaged the deliveries but already had decided to limit his practice to gynecology, which he continues to do in Alexandria. The board did not decide whether he had acted improperly. Nurse Paul V. Rittelmeyer consented to the suspension of his license in 1986 after he acknowledged diverting Demerol, a narcotic, from patients at a Fredericksburg, Va., hospital for his own use. He can seek reinstatement after completing a drug treatment program.

Two years before, the board investigated whether he diverted Demerol at the National Hospital for Orthopaedics and Rehabilitation in Arlington, but it took no action after the diversion was not proved. Attempts to reach him at his last address in the area and through his attorney were unsuccessful. Dr. Gabriel G. Atamian was allowed to surrender his license in 1985, nearly two years after his privileges at the Camelot Hall Nursing Home in Arlington were terminated, according to Board of Medicine records. The board began an inquiry into "numerous and continuous complaints" at the home about the services he provided and into information from peers of "inappropriate and bizarre behavior."

Atamian, who moved to Maryland, said the complaints were unfounded and that his troubles were the result of unfair characterizations made by some New York doctors. He is now studying electrical engineering, and the New York Board of Medicine said his license there remains in good standing. The Virginia board never ruled on the truth of the complaints.

Allegations of incompetence by a doctor take time to investigate and are hard to prove, said Eugenia K. Dorson, Board of Medicine administrator, when asked about the time it took to resolve allegations against some doctors. "Those are difficult, long cases," she said.

Virginia has 10 separate boards that regulate 136,889 licensed health care practitioners. The boards cover doctors, nurses, pharmacists, dentists, funeral directors and embalmers, psychologists, social workers, professional counselors, optometrists and veterinarians. The Department of Health Regulatory Boards, created in 1977, has staff members to do investigations and provide administrative services to the individual boards.

Board officials said the latest numbers, released last week, are the result of concerted administrative and legislative efforts on the part of Virginia's health regulatory boards to clear up a backlog of cases and take quicker action on new complaints.

A new computer system has been installed to improve the tracking of cases, and performance guidelines have been established for staff members to speed up investigations, board officials said. As one of many measures to encourage consumers to bring complaints to the attention of authorities, the boards have started printing a toll-free complaint number (800-533-1560) in red on all new licenses.

The Virginia General Assembly last year strengthened requirements that hospitals report problems they have had with doctors and other health professionals, rather than allowing them to resign and go to new jobs.

Even before recent improvements were made to the boards' investigative procedures, Virginia's Board of Medicine ranked in the top third of state boards in taking disciplinary actions against doctors, according to the Public Citizen Health Research Group, a consumer interest organization. For calendar 1985, the group ranked Virginia's Board of Medicine as tied for No. 13 in serious disciplinary actions per licensed doctors. The District of Columbia ranked 20th and Maryland 43rd.

However, the group argues that even states at the top of its list have not adequately monitored health care abuses. For example, it estimated that, nationally, more than 100,000 injuries and deaths are caused annually by negligent doctors, but that states reported in 1985 taking serious disciplinary action -- revocations, suspensions and probations -- in only 1,089 cases.

"Nationally, they {medical boards} have been ineffective. The fox is guarding the chicken coop," concluded Charles Inlander, president of the People's Medical Society, in a reference to medical boards that consist overwhelmingly of doctors. "They are doing little from the standpoint of policing the profession.

"Even though the number of disciplined doctors in the last two years has gone up, it's nowhere near what it should be," he said.

Inlander said that boards should develop a system of getting reports of all malpractice suits filed against doctors, which now may never come to the board's attention.

Federal legislation passed last year mandates creation of a national data bank and requires reporting of disciplinary actions by hospitals and medical boards as well as any medical malpractice claims paid by insurers.

State medical boards will be able to check on actions taken in other states, and hospitals will be required to check a doctor's record with the data bank before giving the doctor hospital privileges.

The Federation of State Medical Boards in Fort Worth has a computerized data bank that tracks disciplinary actions taken by the states.

Even critics of medical boards agree that it has been effective in keeping doctors banned from practice in one state from simply moving their practices to another.

"In the last three or four years there has been a rapid acceleration" of board activity throughout the country, said Bryant L. Galusha, executive vice president of the federation.

Still, boards have to follow due process when taking disciplinary action, and "you could not believe how long it can take to do what you know is in the public interest," Galusha added.