You should also look at the CDC's website describing what diagnostic tests can be done and when they can be done during the course of the illness, it does not seem like diagnosis is as easy as just testing someone's blood at any given time. Maybe I am wrong, though! See: http://www.cdc.gov/vhf/ebola/diagnosis
You should look up the company GlucoSentient (http://glucosentient.com/technology/). I sent them a brief email about the diagnostic idea a few days ago, I'm sure they are already thinking about this if it is possible to do. Anyways, consider sending them an email!