While union membership in most industries is on the wane or barely holding steady, health care workers from anesthesiologists to x-ray technicians are joining labor organizations at a rapid pace. Some experts believe the trend is likely to continue.

For many health care workers -- including those who work in hospitals, nursing homes and private clinics, as well as some home attendants -- the opportunity to join a union is a relatively new thing. The National Labor Relations Act, enacted in 1935, prohibited employes of nonprofit hospitals and health care facilities from joining unions until 1974, when health care amendments to the act were passed to include them. Since then, health care union membership has risen 20 percent, and is up 6 percent since 1980, according to a 1986 report by the American Hospital Association.

Union membership in other industries, by comparison, has fallen 5 percent since 1980.

In some cases, union contracts may influence such things as how many people are on duty at hospitals and therefore the quality of care.

Enrollment in unions among general industry workers peaked in 1972 and 1973 because of high unemployment and the poor economy. Just a few years later, not-for-profit hospitals began meeting competition for the first time from the for-profit sector, and states began cutting expenditures for hospital building and expansion. As hospital employes began facing changes in benefits, lower pay raises and layoffs, they started joining unions.

Union representation in hospitals in the District is mixed. At some, such as Greater Southeast Community Hospital, there were union efforts in the '70s, but the workers have remained unorganized. At Washington Hospital Center and Howard University Hospital, both the nurses and the services employes are organized.

Nationwide, hospital workers have been far more successful than their nursing home or home attendant counterparts at organizing. Consequently, union representatives say, hospital salaries are as much as 40 percent higher than those of nursing homes for technicians, orderlies and practical nurses.

And between hospitals, salaries for union staff tend to be as much as 30 percent higher than for those whose contracts are not negotiated collectively, according to Robert Muehlenkamp, executive vice president of the National Union of Hospital and Healthcare Employees, whose membership has grown from 15,000 in 1974 to 75,000 today.

Others, however, say such comparisons are exaggerated or misleading. Because unions are most common in coastal metropolitan areas -- where salaries are higher to begin with -- the financial benefits of union membership may be overstated, according Karen Hawley Henry, managing partner for the labor employment law department at the San Francisco law firm of Weissburg and Aronson.

In San Francisco, union x-ray technicians earn $13.95 an hour and nonunion technicians earn $13.33. In Atlanta, where there is little union representation among hospital workers, x-ray technicians earn $8.90 an hour, according to 1985 a survey by the Bureau of Labor Statistics.

Wages vary quite dramatically within the District as well. According to a 1986 Hospital Council National Capital Area Survey, nurses here earned, on average, $12.20 an hour, with the smaller suburban hospitals paying least.

At D.C. General Hospital, where salaries are negotiated by collective bargaining, the average hourly wage was $13.95. Washington Hospital Center, also unionized, had an average hourly wage of $14.80.

At Georgetown University Medical Center and George Washington University Medical Center, where the nurses are not union members, salaries were $12.72 and $12.42 an hour, respectively -- above the average but below the union salaries.

As growing competition and cost squeezing continue at hospitals, however, wages are becoming secondary to job security and benefits concerns. Salary increases have tended only to keep pace with inflation.

"Union representatives have been responsible with regard to wages in the last few years," says Bill Hoffman, an official who negotiates for management at the Washington Hospital Center. "They have negotiated realistic economic packages and haven't tried to exceed the inflation rate."

The economic reality is that 71 community hospitals closed in 1986, the largest number of closures in a decade. American hospitals also closed 10,000 beds in 1986, the third consecutive year of downturn. And the number of hospital employes, excluding doctors, according to the American Hospital Association, fell by 133,000 between 1982 and 1986.

In such a climate, job security and benefits become increasingly significant parts of the contract.

At Children's Hospital, for example -- where all of the interns and residents are represented by the Committee of Interns and Residents, an organizing group representing interns, residents and fellows in New York, New Jersey and the District -- the house staff, as the doctors in training are called, voted not to take an increase in salary when the hospital was in financial trouble four years ago. Since then, the hospital has gotten back on its feet, and increases have been put back into the contract.

Dr. Vinay Nadkarni, a third-year pediatrics resident at the hospital, says that the Children's Hospital House Staff Association (it's not called a union because the National Labor Relations Board doesn't recognize students as union members) has been beneficial by bringing issues to the administration that otherwise might have gone unnoticed. "Our contract," says Nadkarni, "guarantees maternity leave, for example, and gives us a chance to have a loud voice."

Nadkarni's wife, Ellen Deutsch, is a third-year resident at the University of Maryland Hospital, where there is no house staff association and the interns and residents have no say in the contract.

Increases in union members' wages in 1985 -- the most recent year for which figures were available -- in the health care industry were 4 percent, about 0.3 percentage points more than union members in all industries.

Today, health care workers are beginning to turn more of their attention to inpatient care. Because of increasing pressure to release patients early and perform minor surgery on an outpatient basis, "the patients who are admitted to hospitals these days tend to be sicker," says Julia Fry Gibson, director of labor relations for the American Nurses Association, which has organized about 14 percent of the country's 1.7 million nurses.

"One key reason for organizing," says Gibson, "apart from job security and compensation, is to allow the nurses some input into the decisions that will be made in the workplace.

"Nurses have been able to have input into policy decisions that impact the delivery of nursing care, including staffing, purchasing and hospital scheduling," she said.

Doctors, too, are concerned that they are losing clout because decisions on technology and expansion are made more and more by administrators. The Group Health Association of Washington, the only health maintenance organization in the country in which doctors are unionized, employs 157 doctors, most of whom are members of the Capital Alliance of Physicians, an independent union.

Doctors struck the HMO for 25 days last year, protesting management's request that more of their 35-hour work week be spent in the office instead of deducting time for conferences and meetings. The settled contract, which called for only a 3 percent pay increase during the first year of the agreement and a 1 percent increase for the second and third years, also appointed a management-physician committee to decide on an incentive system to increase productivity.

"Doctors are the last of the prima donnas," says Dr. Sanford Marcus, president of the Union of American Physicians and Dentists, which negotiates contracts or acts as advocate for 43,000 of the nation's 550,000 doctors. "Doctors never had to live in a competitive environment, and the idea of negotiating is something that was never taught in medical school."

Membership in the union has quintupled in the last five years, says Marcus, "now that the decisions that used to be left to just the doctor and patient are increasingly being made by third parties."

As hospitals continue to merge and close, service employes stand to lose the most. Staffing patterns, according to AHA statistics, are about four employes to one patient, including outpatients, who require less attention. But that's far too high at current occupancy rates, and in the first quarter of 1987, that ratio has already dropped slightly compared with last year.

Orderlies and technicians are the most vulnerable to being laid off, so some unions have incorporated retraining clauses into their contracts. Local 722, for example, which represents service employes at Washington Hospital Center, Children's Hospital and seven outpatient clinics, has asked for and gotten retraining programs for its 2,000 members. Marchel Smiley, 32, who has been the local's president for seven years, is now a sterilizing processing technician after starting as an orderly at Washington Hospital Center 13 years ago. The hospital began training programs for sterilizing technicians and licensed practical nurses several years ago at the union's request.

The future of unions in the health care industry hinges on what employes realistically expect from their representatives as cost cutting and hospital closures continue.

Another factor that will affect the future of unions in health care is a meeting next week of the National Labor Relations Board to discuss rules governing the composition of health care bargaining units.

At issue is whether hospitals should be limited to two units apiece -- one professional, one nonprofessional -- or whether any group of workers should be permitted to organize on its own. Most hospitals prefer bargaining with one large union rather than many small ones because such an arrangement leads to fewer strikes.

Gerald Shea, head of the health care division of the Service Employees International Union, which has 850,000 members, of whom 290,000 are health care workers, says that the unions have a goal of having 50 percent of all health care workers organized by the end of the century, double the current number.

With unions' dues ranging from $150 to $250 annually, that's important income for unions. But as wage increases fall and benefits and job security become vulnerable, it remains to be seen whether health care workers will think that's money well spent.

Fran Lunzer is a New York free-lance medical writer.