Verax is currently developing a version of its PGD test to address the risk of bacterial contamination in red blood cells. While the risk of red blood cell contamination is lower than the risk of platelet contamination, at 1:20,000, it is the second largest infectious risk for the nation’s blood supply and far exceeds the risk associated with transfusion-transmitted viruses such as HIV, HCV, and WNV. Red blood cells are stored under refrigeration which limits the growth of many of the bacterial species that thrive in platelets. Some species, however, flourish in a refrigerated environment and are capable of reaching harmful levels during the significantly longer storage periods of red cells (up to 42 days vs. five days for platelets). Red blood cells tend to be contaminated with gram-negative bacteria such as Yersinia enterocolitica and Serratia Sp., which release endotoxin during storage and give rise to a greater rate of septicemia and fatal reactions.
Red cell contamination has frequently been linked with fatal transfusion reactions with three of the nine fatalities reported during the U.S. Bacterial Contamination (BaCon) Study performed by the Centers for Disease Control attributable to contaminated red cell units. In Verax’s internal preclinical studies for the Platelet PGD Test, one of the four contaminated platelet units identified by the test was linked to a contaminated companion unit of red blood cells that came from a whole blood donation only 10 days old.