I subscribe to the APIS newsletter and clicked on a link in the newsletter for varroa detection and it took me here:
COLOSS is a non-profit association of various scientists, students, agricultural extension specialists and veterinarians from around the world. They put together a Beebook which includes varroa information such as the link above. I found the various methods of varroa monitoring interesting and will be reading the remainder of the Beebook as I have time.
As I read the BROOD EXAMINATION section, I noticed that the instructions called for the cells and pupae to be flushed out. I guess that is to dislodge mites that may be lingering in the cells. There is also a link to a picture of the poop left by mites which I found very useful.