Pathology laboratories are in agreement that fixation is the key to maintaining cellular morphology and optimal staining of tissue. However, laboratories differ in their emphasis on time allowed for proper fixation and decalcification. The rate of tissue fixation is dependent on various factors including the type of fixative used. Formalin is a rapidly penetrating fixative, but needs up to 24 hours to cross-link and completely stabilize the proteins within the tissue. If decalcification is required after fixation, another day or two must be added to the turnaround time. In high volume laboratories with expectations for rapid turnaround time, this may not be an option.
Calcified tissue fixation can be done in one of two ways:
- Fixation prior to decalcification
- Fixation during decalcification