Once the virus behind AIDS had been identified, as described in HIV Discovered, the most urgent practical need was a way to keep it out of the blood supply. People with hemophilia, who depend on products made from donated blood, and patients receiving transfusions were being infected, and blood banks had no test that could detect the virus.

On March 2, 1985, the US Food and Drug Administration licensed the first test to screen donated blood for antibodies to the virus, then called HTLV-III. It was developed by Abbott Laboratories after about nine months of round the clock work by its scientists. Health and Human Services Secretary Margaret Heckler and FDA Commissioner Frank Young announced the approval at a crowded news conference in Washington. The first test kits shipped to blood banks on March 4, 1985, and the American Red Cross and other blood organizations adopted the test immediately.

The test detected antibodies, the body's response to infection, rather than the virus itself, and…