Bovine Whole Blood Assay (bWBA)
The test works by taking the whole blood from the animal and introducing
it to a solution containing the pharmaceutical being tested
69. In response to endotoxin, the white blood cells in
the blood produce the cytokine Prostaglandin E2
(PGE2) in an inflammatory response, similar to that of
humans 70. The production of this cytokine is directly
proportional to an increase in endotoxin concentration. According to
several studies, the test is able to accurately detect endotoxins at
concentrations of close to 25 pg/ml, whereas the concentration at which
humans display symptoms of endotoxin exposure typically occurs around 30
pg/ml 70. This level of accuracy is very attractive
for scientists looking to move away from LAL and RPT testing. The test
also is easy to perform and takes few preparational steps
23. The test is not without its limitations. The whole
blood needed for the tests can only be obtained from very young calves
which makes it difficult to amass in vast quantities
71. Furthermore, due to cultural and religious
practices, certain countries will not permit the collection or use of
bovine blood. While its accuracy and ease of use is admirable, it still
requires animal testing, and with the advancement of technology, this
test may be replaced by other techniques.