WHAT IS THE AIDS TEST? -- It is a blood test introduced last spring to help the nation's blood banks eliminate blood contaminated by the AIDS virus, known as HTVL-III.

*WHAT DOES THE AIDS TEST DO? -- It detects the presence of antibodies to the AIDS virus in the blood. It is not a test for the disease itself.

*WHAT DOES A POSITIVE TEST MEAN? -- It means that an individual may have been exposed to the HTLV-III virus and have developed antibodies -- substances produced by white blood cells to fight infections.

*DOES A PERSON WHO TESTS POSITIVE HAVE AIDS? -- A positive test does not mean that a person has AIDS or will develop the disease, or that the virus is still present. Nor does it mean that the person has developed immunity to the disease.

*HOW MANY PEOPLE WHO TEST POSITIVE EVENTUALLY GET AIDS? -- Researchers estimate that 5 percent to 20 percent of people exposed to the virus eventually will develop AIDS. An estimated 500,000 to 1 million people are thought to have been exposed to the AIDS virus.

*WHAT KINDS OF AIDS TESTS ARE THERE? -- Two. The more common is the ELISA test, meaning enzyme-linked immunosorbent assay. It has a high rate of false positives -- results incorrectly showing exposure to the virus. A more complicated and expensive test, the Western Blot, is usually done on positive ELISA results.