To protect it, the American Red Cross long ago started testing the blood of all volunteer donors. But in poor regions of the world, such vigilant screening is out of the question. In parts of Africa, for example, nearly 30 percent of all blood donors may go untested in a given month because there is not enough money to procure test kits for everyone.
Doctors test as many as they can.
The rest is left to chance. The human consequences are devastating. Testing for AIDS is a difficult problem in which Stefanos Zenios, ssistant professor of operations, information, and technology at Stanford's Graduate School of Business, has taken a keen interest. Using advanced statistical analysis, Zenios and Lawrence Wein, MIT professor of management, have devised an accurate way to test more cheaply by pooling blood samples. If a batch of 10 samples produces a negative result, then the cost of nine tests has been saved.