Anyway, my only chance is to give it a try. And I also hope there will be good research coming up on this topic!It's a reasonable statement, but the functional word is "can", not "always". Chia knows how to do it, he's done it in his studies, it's just not something he's equipped to do at scale on a clinical basis. Others have as well (I linked two previous studies that found enterovirus RNA in spinal fluid, not important to read if you are too sick to, just be aware they exist). I can't give you a figure on how quickly, but for example in Chia's previous studies he mentioned he would literally have to take the blood immediately after having it drawn and drive it back to the lab to spin down and process, and even doing so would net very very low copy numbers with qPCR. No commercial or nationalized health system that I'm aware of will use RNA preservatives in the tubes when they draw your blood/CSF for PCR testing, nor will they be guaranteed to process it with any rapidity, nor are you guaranteed that there happened to be any meaningful quantity of cell-free RNA in the few ml of blood they drew.
If enough interest and evidence can build around this idea, I really hope that there will be improvements in clinical testing of enteroviruses so it can be dragged out of the 20th century ideology behind the testing that's barely available even today.