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.