Arlington jail inmates who test positive for the AIDS virus will be isolated from other prisoners, Sheriff James A. Gondles Jr. said yesterday, reversing his longstanding position that such inmates remain in the general jail population.

Gondles also broadened his policy on testing inmates for the disease. Until now, the jail tested only inmates who showed symptoms of the disease and those who paid for the test themselves.

Under the new policy, inmates who request the test will be given it free if they have a history of intravenous drug use, have had a blood transfusion prior to 1985, are bisexual or homosexual, or have had multiple sexual partners. Medical personnel also may perform the test in light of other relevant circumstances.

Gondles said his decisions were prompted by a recent incident in which an AIDS-infected prisoner bit another inmate. The bitten inmate filed suit against the sheriff to force jail officials to test him for the AIDS virus. He was given the test, and it was positive. There is no evidence that he contracted the disease from the bite.

"I'm trying to put myself in their shoes," Gondles said. "If I were in a cell block and someone {next to me} had tested positive, I would be wondering whether or not he would physically assault me."

Under the new policy, inmates who have tested positive for AIDS will be put in medical isolation on the fourth floor of the jail. They will be allowed to be with other inmates under supervised situations, such as classroom instruction and exercise classes.

AIDS testing and isolation policies vary from jail to jail throughout the Washington area. Many policies are under review, jail administrators said yesterday.

Jail officials said they recognize that they are dealing with a high-risk, often violent population, in which rape and homosexual activity occurs.

But they also acknowledge the great psychological and financial burden of isolating AIDS carriers in jails that are, in many instances, becoming crowded.

"We have a high-risk population. We could end up with 200 to 300 inmates in our charge who tested positive," said Fairfax Sheriff M. Wayne Huggins. "I do not have the physical capacity to house them."

In Fairfax, inmates are not isolated and tests are given only if the jail's medical personnel have determined there is some reason to believe an inmate may have come in contact with the disease.

Alexandria Sheriff James H. Dunning said AIDS carriers in the jail there are isolated. Until now, however, the jail has had only cases of inmates with advanced AIDS-related illnesses, and none who had simply tested positive.

In the District, only inmates who exhibit AIDS symptoms are isolated.

Inmates in Montgomery County are segregated, while in Prince George's County it is up to the medical staff to determine whether an infected inmate is likely to act responsibly in the general population.

Arlington Sheriff Gondles said he changed his policy after consulting medical personnel, and announced it to his staff this week.

"I don't feel real good about {changing the policy}," Gondles said. "To protect the people who don't have AIDS, we are penalizing {some} people who test positive who wouldn't be a problem."