The regular bloodwork generally tells them things like liver function, kidney function, white blood counts, etc. I think they are more about whether you can take more chemo or need a break, or may need something to build your blood counts back up, etc. Chemo is cumulative and gets harder as it goes along, so once the treatments are done, he should start to perk back up again. After chemo rounds, we generally did a CT, and frequently a PET also to see if there was measurable response in cancer growth.