I was told by a co-worker: the longer tissue is kept
in formalin, the more it losses its staining
properties.  We were discussing keeping wet tissue vs.
blocks for back up special stain/immunohistochemistry
controls.
  Does it really matter how long the tissue is in   
formalin?
  What are the effects of tissue kept too long in   
formalin?
  It is ideal to have 5-10 year old blocks to use as  
    controls?
I know that this question seems a little generic, but
I'm still a rookie!! :)

Michelle Lowe
Sup. Anatomic Pathology/Histology
Valley Children's Hospital
Madera, CA 
__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com