2 Tests Generally Used to Confirm the Presence of AIDS Antibodies

Laboratories generally use two tests to confirm the presence of AIDS antibodies.

If a person carries those antibodies, that means he or she carries the AIDS virus, although he or she may not have developed the symptoms of acquired immune deficiency syndrome or AIDS-related infections ranging from swollen glands to tumors.

The most common screening test for AIDS antibodies is called the ELISA test--for enzyme-lined immunosorbent assay. If that test is positive, its results are generally confirmed by a second, more expensive and more time-consuming laboratory procedure called the Western blot.

Negative Result Not Always Last Word

AIDS experts warn, however, that there is a “window” of from several weeks to as long as six months when a person can be carrying the AIDS virus but still not test positive for the deadly virus with either test.

These are the “false negatives,” noted William Argonza, acting chief of laboratory field services for the state Department of Health Services.

“If the results are negative, it doesn’t mean you do not have the disease,” Argonza warned. He recommended that those who believe they may have been exposed to the AIDS virus be tested more than once.