Earlier in this thread, DJE posted a comparison between blood and that of peanuts. "Abstain from blood" could be compared to "Abstain from peanuts". At the time I meant to call him on that, bucause the "peanut" is a divisable thing and it' can have it's allergen removed. Technically, people arn't allergic to peanuts, they are allergic to part of the chemical composition of the peanut. In the past, removing those parts have been difficult and expensive and also ruined the taste...
(Quoting Wikipedia):
Allergen-free peanuts
On July 20, 2007, the North Carolina Agricultural and Technical State University announced that one of its scientists, Dr. Mohamed Ahmedna, had developed a process to make allergen-free peanuts. Initial testing showed a 100 percent deactivation of peanut allergens in whole roasted kernels, and human serums from severely allergic individuals showed no reaction when exposed to the processed peanuts. Food companies have expressed an interest in licensing the process, which purportedly does not degrade the taste or quality of treated peanuts, and even results in easier processing to use as an ingredient in food products. [ 35 ]
Comparing them further, we should be able to remove the "god allergen" from the blood and be able to use it.