A diagnostic test for the Human Immunodeficiency Virus using saliva samples is now being tested in humans, following approval by the Food and Drug Administration.

Officials at Epitope Inc., a company based in Beaverton, Ore., say that the test could prove helpful in situations where blood samples are difficult to obtain, such as from newborns who have tiny veins and from intravenous drug users whose veins have collapsed. If widely used, the new test could reduce the risk to health care workers who must draw blood samples to test for the virus, according to John Fitchen, medical consultant to Epitope.

The test involves pressing a cotton fiber between the cheek and gums for approximately two minutes. The fiber is then tested for the presence of antibodies to HIV, which indicates infection with the virus. Although saliva is believed to contain minute quantities of the AIDS virus, it has not been documented as a means of AIDS transmission.

Clinical trials of the saliva test are under way at San Francisco General Hospital, and four other institutions are comparing the HIV-detecting ability of the saliva test with a standard blood test in 4,000 pairs of blood and saliva samples. Epitope officials say the experiments are expected to last nine months.