On opening the box of sensors I was shocked to read that the sensors actually have human serum derivatives in the sensor probe. When we did our trial the leaflet was not in the box of sensors. I would have preferred to have received this info before the trial so I could make an informed decision about whether to use them on our daughter. I have asked Medtronic to answer the following questions; The operator told me there was a permeable barrier over the sensor to allow glucose into the probe. Are the permeable "holes" large enough to allow prions through? Viruses? This is a blood byproduct isn't it? (ie. not sourced from cadavers.) Where do you source the blood and what screening systems are in place for it? (And it's donors) Is the blood sourced from America? What size the donor pool of blood is and at what temperature and for how long is the blood used pasteurized? And - is there a chemical step in the purification process. Has anyone else asked these questions? I am eager to find the answers to the above questions quickly as I was hoping to use the sensors on a school trip. The donor pool question is because the chances of contamination increase proportionally to the size of the donor pool.