Well, you won't find that documentation, but here is some logic. The ProVue is the automated instrument for the gel system. When you prepare it for the day, you load a number of IgG cards onto the 37C rack. Guess what happens to the card or cards not used? They stay in place until you use them. That may be several cycles. At one time we acted conservatively and didn't load more than we could use, but as with many things, familiarity breeds not contempt, but relaxation. No harm has ever come to the cards. And think about it, the cards are sealed and the temperature does not rise above 37C, hardly a level to cause degradation.