I'm definitely not recommending ignorance, generally speaking. Just pointing out that if you go looking for viral DNA in blood, you'll likely find it in a lot o

I'm definitely not recommending ignorance, generally speaking. Just pointing out that if you go looking for viral DNA in blood, you'll likely find it in a lot of samples that would otherwise be considered acceptable for transfusions. The latest techniques are finding trace viral DNA in plenty of human samples previously deemed "negative." (1) Now what do you do? Technically, you've found contamination that might or might not lead to disease. Is the blood usable or not? The point is that we know which pathogens that we need to look out for in transfused blood. Better to continue with targeted tests for the pathogens that actually cause important human disease rather than just fish for everything you can find. And don't get me wrong, this technology could be really useful for better understanding epidemiology or understanding the common viral contents of human blood--I'm excited about the possibilities. I just wouldn't use it in the context of blood banking as I don't think it adds anything helpful (unless we are faced with a novel virus in the future that is being transmitted through blood and needs to be identified). 1. http://www.researchgate.net/publication/274394532_Small_circular_single_stranded_DNA_viral_genomes_in_unexplained_cases_of_human_encephalitis_diarrhea_and_in_untreated_sewage http://www.researchgate.net/publication/274394532_Small_circ...