The Department of Health and Human Services is expected to announce today new national guidelines on acquired immune deficiency syndrome (AIDS) in the workplace that generally recommend against routine screening to see who may be infected with the virus and against employment restrictions on individuals known to be infected.

The guidelines say that such steps are medically unnecessary because there is no evidence that AIDS is spread by casual contact of the type that occurs in most occupational settings.

The guidelines counter controversial proposals by legislators in several states and the Congress to test certain groups of workers, such as food handlers, teachers and health care workers, and impose restrictions on those found to be potential AIDS carriers.

The recommendations, scheduled to be announced at a news briefing today by acting Assistant Secretary for Health Dr. James O. Mason, apply to people in jobs where there is no known risk of AIDS virus transmission as well as to health care employes who may be exposed to AIDS in their jobs. The rules will be published Friday by the federal Centers for Disease Control.

HHS has already issued guidelines suggesting in general that children with AIDS should be allowed to attend school with evaluation on a case-by-case basis.

The new workplace guidelines emphasize that "AIDS is a blood-borne, sexually transmitted disease that is not spread by casual contact." They "do not recommend routine AIDS antibody screening" for workers in general, according to a document being readied for final printing yesterday.

The AIDS antibody blood test indicates that a person has been exposed to the virus and may be a carrier who is infectious to others. It does not indicate who may contract the disease. While there have been more than 14,000 reported AIDS cases in the United States, half of them fatal, experts estimate that about 1 million Americans may be carriers, most of them apparently healthy.

"Because AIDS is not transmitted through preparation or serving of food and beverages, the guidelines state that food service workers known to be infected with AIDS should not be restricted from work unless they have another infection or illness for which such restriction would be warranted," according to a summary of the recommendations.

With regard to health care workers, the guidelines urge that precautions be taken in dealing with blood or bodily fluids in which the AIDS virus might be transmitted, precautions that are already taken in dealing with infectious diseases such as hepatitis B.

The government guidelines say that health care workers who are known to be infected with the AIDS virus generally need not be restricted from work on this basis because there is "no evidence" that the virus would be transmitted to patients under most circumstances.

The guidelines do add a note of caution that there is a theoretical risk of AIDS transmission in major medical procedures in which there could be significant blood exchange between worker and patient. The document says that more specific recommendations are still in progress for health care workers, such as surgeons and dentists, who perform "invasive procedures."

Sources inside and outside the government said that the substance of the guidelines, circulated in printed form to experts who advised the government in their preparation, was not expected to change.

The advisory committee, including experts from most major medical groups, affected businesses, such as restaurants, as well as representatives of groups at high risk, reached a consensus last month that employment restrictions were generally not warranted from a health standpoint.

But top HHS officials questioned whether the government recommendations should go further, particularly whether there should be screening of hospital workers or people admitted to hospitals to see if they are infected.

Instead, the guidelines say that routine blood screening of all patients for the AIDS antibody is unlikely to reduce the risk of AIDS transmission in the workplace, which "even with documented needle sticks is already extremely low."

Only three health care workers in the United States are thought to have been infected in the course of employment. The guidelines say that "some hospitals in certain geographic areas may deem it appropriate" to initiate blood testing of patients.