Researchers have discovered that the AIDS virus apparently may become dormant in the human body and undetectable by the standard test but say the finding does not mean the nation's blood supply is endangered.

"The blood supply is exceptionally safe and protected to a great extent by existing screening tests and the self-deferral of individuals at high risk," said B. Frank Polk, a professor of epidemiology at the Johns Hopkins School of Public Health and co-author of the study published in June's Annals of Internal Medicine.Tests to pinpoint the disease and protect blood supplies are based on detection of HIV-1 antibodies, produced naturally by the body to fight the acquired immune deficiency syndrome virus.

The instances of AIDS victims who stop producing detectable antibodies to the disease appear to be rare and so far have only been observed in those who have shown small amounts of the virus in their bodies, said Homayoon Farzadegan and Alfred J. Saah, also professors of epidemiology at Hopkins and authors of the study.