There is no standard formulary that I am aware of that covers all of the many
variables involved in calculating the shrinkage of tissue during 10% NB
formalin fixation. Many of the factors to consider are the thickness and type
of tissue, fixative salt, osmolarity of the fixative, pH, temperature,
concentration of the fixative and the time spent in it.

The most important factor to consider is that tissue shrinkage is not caused
only by the formalin fixation, but by the dehydration, clearing and the
subsequent paraffin impregnation (with and without vacuum pressure in closed
system processors) that follows fixation alone.



Eric C. Kellar
University of Pittsburgh Medical Center



-----Original Message-----
From: Jennings, Margaret A.
To: histonet@pathology.swmed.edu
Sent: 8/25/00 2:12 PM
Subject: shrinkage



 What is the formula for shrinkage when using 10% neutral buffered
formalin
to fix  a tissue sample? If I start with a tissue a microns x  b microns
x c
microns what do I end up with? Is there a time factor for additional
shrink?
Is there also a formula for rate of penetration? Formalin infiltrates y
microns per t? What about other fixatives any formulas available?