A blue shading in the grading sheet means that this is an optional order. It will look something like this:
Some people will be upset that it will be marked blue even if they order it thinking that if they ordered this it will be marked as green. The program will mark this order as blue whether it is ordered or not. The point of the blue is to point out that this lab result would be abnormal or to draw attention to the order as a good idea to order which may or may not get points on the USMLE.