August 9, 2002
Officials with the Food and Drug Administration and the nation's blood banks are in agreement on making America's already safe blood supply even safer. However, many are concerned about the effects of the new pathogen reduction procedure, and some think the tradeoff will create more problems than it solves.
"It will be up to the blood banks to tell us if it's worth the tradeoff," said Dr. Jaro Vostal, an FDA medical officer and chair of this week's conference at the National Institutes of Health on experimental blood-cleansing procedures. Dr. James AuBuchon, head of pathology at Dartmouth-Hitchcock Medical Center, put the question of risks in a more scientific light: "If the risk of HIV or [hepatitis C] is one in 2 million units, what risks should be acceptable? And how can we prove they are this small?"
While FDA officials and blood researchers say they aren't particularly concerned about HIV and hepatitis C because tests since 1999 have cut the risk of infection to one in 2 million, they are concerned about a range of bacteria present in about one in every 2,000 units of blood that may sicken or even kill an estimated one in 100,000 transfusion recipients.
Pathogen reduction works by adding a chemical to platelets to make pathogens more sensitive to light, then zapping them with ultraviolet light. Other systems use chemicals to destroy the pathogens. In both cases, the chemicals are then washed from the blood. However, while pathogens are destroyed, so is the survival time of platelets, with a 25 to 30 percent loss of them in the process.
Although the platelets that survive the process work fine, the reduction is significant and will require blood centers to collect more blood -- perhaps 100,000 more units of whole blood a year. Already, blood banks barely collect enough blood.
Finally, there is the question of what the unintended effects on patients will be by the chemicals used to cleanse the blood. Most experts agree that these will not be evident for years.