When I do talks on Lyme disease, I'm often asked if the bacteria (Borrelia spp.) that cause the illness are transmissible via blood transfusions. The default answer of health authorities has long been no. However, the worldwide absence of screening tests capable of accurately and consistently detecting the presence of Lyme bacteria in the blood supply makes it difficult to give a definitive answer to that question. Hopefully, once the technology improves and researchers are able to consider the question with the assistance of more accurate tools, the answer will continue to be no, but only time will tell.