Bone and other ossified tissue must have calcium removed for the tissue to be soft enough to section. This is achieved by placing the tissue in a decalcification solution based around an acid. Under-decalcification of tissue prior to processing can result in a number of artifacts in the final sections.
Factors associated with under-decalcification:
(1) not placed in a decalcifying solution
(2) time in the decalcification solution not long enough
(3) weak decalcifying solution (dilution, repeated use, etc)
Artifacts associated with insufficient decalcification:
(1) residual calcium in the tissue, which will stain blue in an H&E section
(2) poor section quality due to poor cutting
Ways to avoid:
(1) Use an appropriate decalcification solution and follow manufacturer’s instructions.
(2) Place in the decalcification solution for a sufficient period of time.
(3) Cut pieces of bone small and/or thin so that there is rapid penetration.
(4) Monitor the tissue during decalcification, which may include taking X-rays.
Often sufficient decalcification can be achieved by placing the exposed tissue in the paraffin block face down in decalcifying solution for 30-60 minutes.
