Most Sundays, Gloria S. Fincher bends toward her 82-year-old mother and tells her a little white lie -- a lie, she hopes, that will afford a bit of solace.

"I'm just going out to eat," she tells her mother, and then she slips from the nursing home in Berryville -- 40 miles west of Fairfax -- not to return until the following weekend.

"I used to tell her I'd see her next weekend, but she'd get upset and say, 'Don't leave me here,' " said Fincher, a receptionist with a Fairfax County government office who lives in Manassas, a 90-minute drive from her mother's nursing home. "If she was any closer I'd stop by and see her but the nursing home is just too far away."

Fincher's mother is on a growing list, compiled by area health officials, of more than 300 of the poorest, sickest and most dependent elderly people in Northern Virginia who have been forced to find nursing home care far outside this area.

The primary reasons are a shortage of nursing home beds in the Virginia suburbs and a dramatic cutback in the number of Medicaid patients some nursing homes are accepting. Medicaid is the federal health-care program for the poor, which is administered by the state under rules that vary from jurisdiction to jurisdiction.

The problem has been aggravated in Northern Virginia by a state policy placing a cap on payments to people receiving Medicaid. That's made nursing home operators reluctant to build additional beds in the Washington suburbs to care for Medicaid patients -- a problem not experienced elsewhere in the state, where nursing home costs are lower. Neither the District nor Maryland has reported having the problems Northern Virginia is experiencing.

The change in Virginia's policy governing Medicaid payments to nursing homes occurred three years ago.

The state no longer reimburses nursing homes for costs they have already incurred, but instead sets a flat rate of daily payment. That daily payment to nursing homes, which typically runs about $50 per patient in Northern Virginia, is not enough to make a nursing home profitable, according to some home operators.

"We're running at a loss for every Medicaid patient we have," said Gina Mitchell, assistant administrator of Powhatan Nursing Home in Falls Church, where fewer than one-third of the patients are Medicaid recipients.

Health-care specialists and nursing home operators cite a combination of factors that have produced the nursing home bed crunch, including a rapidly increasing elderly population in Northern Virginia. They agree that the emotional burden of long-distance separations falls most heavily on the nursing home patients in the area who receive Medicaid.

"To have to send a person three or four hours away to a nursing home is tragic," said Katie F. Conrad, a Fairfax County health planner. "We're not talking about people who function well or who know what day it is often. And for these people to be cut off from those who love them and whatever they have left in life is very sad."

Last year, of 1,546 Northern Virginia Medicaid patients, 331 of them -- more than a fifth -- were placed in nursing homes outside the region. From Fairfax County, by far the largest jurisdiction, 160 elderly people were placed in facilities as far away as Williamsburg, Charlottesville, Virginia Beach and Richmond, all two hours or more away by car.

About 60 percent of those requiring nursing home care in Northern Virginia are eligible for Medicaid, or become so once their savings are exhausted. For middle-class patients, savings can be depleted quickly -- nursing home bills in this area run about $25,000 a year.

Powhatan, like every other nursing home in Northern Virginia, is a private profit-making facility. It provides one example of the impact of the state's new policy.

Until the late 1970s, three of four Powhatan patients received Medicaid at the 160-bed facility and patients were admitted on a first-come, first-served basis. The change in pay plans at the state level led Powhatan to reduce by attrition its roster of Medicaid patients.

Now, administrators there say, private patients, for whom the daily rate is $65, effectively subsidize the Medicaid patients.

Mitchell said Powhatan no longer admits new Medicaid patients; those at the nursing home who are on Medicaid stopped paying for their own care themselves after they ran out of money.

Fincher encountered local nursing homes' attitudes toward Medicaid patients when she tried to find a bed for her mother in 1983.

"We must've gone to 10 different places; they wouldn't even take your name," she said. "When you say Medicaid they kind of change their tune."

"It really is an emotional experience to have to turn away the families of Medicaid patients," said Powhatan's Mitchell. "We don't like it at all."

Northern Virginia politicians and state legislators say they like it even less.

The Fairfax County Board of Supervisors has urged nursing homes to accept patients on a first-come, first-served basis.

Nursing home administrators say that plan is unworkable because it would force them to pair grossly incompatible patients in one room -- an Alzheimer's disease patient, for example, might have to share a room with a lucid patient recovering from a broken hip.

Del. Mary A. Marshall (D-Arlington), a key state legislator on the issue of nursing homes, hints that she may threaten the industry with legislation requiring first-come, first-served policies if facilities do not cooperate to ease the plight of Medicaid patients.

"The problem has got to be solved, and first-come, first-served is a solution," she said. "It's just outrageous that some of our people should have to go hundreds of miles out of the area to find a bed."

Some nursing homes in Northern Virginia do have a majority of Medicaid patients among their residents. Marshall and other state officials point to those homes as proof that Medicaid can cover patient costs and even help produce a profit for a nursing home.

Peter C. Clendenin , executive director of the Virginia Health Care Association, said, "It is very difficult to run an efficient facility at the Medicaid rate, but I think it is possible."

He said that a nursing home could break even or profit at the Medicaid rate only by shedding amenities, such as plush furniture and large-screen television sets. "You can provide good services, but you cannot provide the best services under the Medicaid rate," Clendenin said. "It's like the difference between a Chevrolet and a Cadillac."

Some nursing home operators say they favor a system, similar to Maryland's, under which the state would make Medicaid payments to nursing homes according to the particular medical needs of the patients. Under such a plan, for example, nursing homes would merit larger Medicaid payments for incontinent patients who require continual attention than for relatively well patients.

The Virginia General Assembly has allocated $100,000 for a study of such a system, to be ready before the legislature meets next January.

Officials say, however, that legislators are likely to frown on any proposal that will significantly increase the state's Medicaid outlays, and nursing home administrators are doubtful about any new policy that does not increase overall payments.

Clouding the outlook for nursing homes under increasing pressure to accept Medicaid patients is a stark fact of demographics: Northern Virginians are getting older.

Last year, the Virginia suburbs had about 77,000 people over the age of 65, according to the Health Systems Agency of Northern Virginia, a planning group.

By 1990, HSA says, there will be 97,100 people of that age in the area.

That means not only that the demand for nursing home beds is likely to keep rising, but that older, sicker and more dependent patients will populate nursing homes, according to health care specialists. Those patients require the most expensive care.

More than 400 nursing home beds have been approved by the state but are not yet built; they are in various stages of planning and construction.

Some officials and politicians, including Del. Marshall, said they hope the shortage of beds has peaked, and that once the new facilities are available, the number of patients who are placed far away from their families will drop.

They acknowledged that they pin their hopes on the development of more popular alternatives to nursing homes, such as health care in the family home.

"The problem can be worked out," Marshall said. "It's not beyond the reach of man."