The removal of calcium deposits is essential for the manipulation of certain tissues in histology. Decalcification usually takes place between the fixation and inclusion steps. This step obviously concerns bones but also other tissues containing zones of calcification. A large number of reagents and methods have been developed for decalcification and each has its advantages and disadvantages. The main methods used are based on the use of mineral acids, organic acids or EDTA.

Decalcifying solutions are used to prepare bones and hard tissue for microscopic analysis. The choice of reagent depends on the hardness of the material, the purpose of the diagnosis and subsequent analysis. The decalcification time is a function of the size and the structural density of the hard tissue, as well as the composition of the decalcification solution.

In order to obtain the best possible results when decalcifying tissues, it is very important to determine the point at which decalcification is complete. Incomplete decalcification can cause tissue distortion and damage the microtome when cutting the tissue. Too much decalcification can cause problems in the coloring, in particular for the coloring of the cores.