It was not a happy sight.

Nineteen-month-old Dante Lewis sobbed hysterically as a Fort Belvoir Army nurse squeezed blood from his pricked finger and a dozen news photographers poked lenses in his tear-streaked face.

But the experience was even more frightening for his mother, Anne-Marie Lewis, and hundreds of other parents who live in a group of apartment buildings on the Army base in southern Fairfax County. They were told last week that the Army had discovered dangerously high levels of lead in paint flaking from the hallway walls of their buildings and that their children would be tested for lead poisoning.

"I felt like I was going to have to move. I was scared," said Lewis, trying to comfort her crying youngster as Army medical teams and volunteer civilian nurses began the massive screening program yesterday. Small blood samples were taken from hundreds of children who live in the 446 apartments in Lewis Heights.

Military officials said yesterday that if symptoms of lead poisoning are found in the children, the Army will begin an even larger-scale search for all of the children who have lived in the housing units since they were built 26 years ago. Final results of the testing will be known in three to four weeks.

Lead poisoning, which can cause anemia and sluggishness in children in its mildest forms and can lead to learning disabilities and mental retardation in its most advanced stages, has been identified as a nationwide problem, especially in inner cities and areas with older housing units. All but the most severe cases of lead poisoning are treatable with medication. Federal regulations have severely limited the amount of lead allowed in paint products manufactured since the early 1970s.

Lead-based paint is considered harmful if swallowed, and medical specialists say young childrenmay eat chips of flaking paint or can ingest the toxic material by running their fingers along the walls and then putting them in their mouths.

Fort Belvoir officials said they have started repainting many of the units in the Lewis Heights area, but said they have no plans to test paint samples from the more than 1,100 other base housing units built before the tighter restrictions were imposed for paint products.

Officials said the flaking lead-based paint was found in basement and hallway areas. Medical personnel reported yesterday they also found chipped paint inside some of the apartment units and they will ask that it be tested for lead content.

Base officialscalled this week's efforts "preventive medicine."

"We don't know yet whether we have a problem," said Col. Peter D. Stearns, acting commander at Fort Belvoir. Military officials said the Army base hospital and medical facilities have not diagnosed any cases of lead poisoning in children, but noted that symptoms of the illness are sometimes misdiagnosed.

The task of collecting blood samples from hundreds of youngsters has not been easy, according to Capt. Diane Rybinski of the base's community health nursing staff.

"We've had to chase some of them all around the room," said Rybinski, filling a vial with blood from the finger of sobbing Marcella Alberico, 4, the daughter of Sgt. Joseph Alberico.