Moreover, hospitals may underreport the problem. O blood for emergency rooms and intensive care units, Klein says. This practice, however, can create a shortage of type O blood for the region. On the other hand, between 5 and 10 percent of A and B blood goes to waste, says Popovsky, simply because hospitals can't use those units within their 42-day shelf life. To minimize the waste of usable blood, hospitals sometimes ship their surplus to other institutions in the region that need more than they anticipated.
Blood also travels between neighboring regional blood centers.
Conversion of all blood to type O can address these supply imbalances and reduce the amount of shipping necessary, says Jack Goldstein of the Kimball Research Institute at the New York Blood Center, who is one of the pioneers in the field. T he idea explored by Goldstein and other researchers is to use an enzyme to alter the chemistry of the red cell surface. The major distinction between types lies with the sugar that branches off from the galactose. On A cells, that sugar is N-acetylgalactosamine. On B cells, it's another galactose.