A CBC is a complete blood count.  It can clue you in to things like
viral and bacterial infections, lymphoma, etc.  It should be done on any
animal going under anesthesia but especially an older animal.  Yes you
should be concerned about your ferrets teeth.  Dry cat food is not
enough to keep the plaque off.  A vet.  can look at your ferret's teeth
and let you know if they need cleaning.
 
[Posted in FML issue 0461]