J, I think that your vet and possibly the lab being used are not familiar
with ferret blood tests, and that your vet doesn't seem to be aware that
a neck stick can be done easily enough on most without anesthesia.  In
fact, when our vet does them the part the ferrets most mind is the
alcohol swab.  Is there a vet in your area who is more familiar with
ferrets?  (Vet lists -- each different -- can be found in the Critical
Refs at http://www.ferretcolngress.org.)  In going on 21 years with
ferrets we have never -- never -- had a ferret have to have anesthesia
to get a blood test.
 
Are you close enough in Texas to Dr. Jerry Murray to go to him?  He knows
what he is doing with ferrets and I have heard only good about him.
You'll find him the assorted vet lists.
[Posted in FML issue 4129]