EDTA Decalcifying Solution (pH 7.2)

Some tissues contain bone or calcification, such calcium-containing tissues should not be directly embedded in paraffin sections. This is because the density between calcium and paraffin is different and it is more difficult to remove the intact section. After the calcium-containing tissue is preferably fixed, decalcification or both are carried out simultaneously. Subsequent experiments such as dehydration, transparency, waxing, embedding, and sectioning are then performed. There are many reagents for decalcification, and decalcifying agents include organic acids, inorganic acids, EDTA, and electrolytic decalcification.

EDTA is a relatively good chelate decalcifying agent, which has the least influence on the structure of the tissue and it can better preserve some enzymes in tissues. The tissue decalcified by EDTA can be used for IHC and in situ hybridization.

Advantages of EDTA decalcifying solution:
1. Tissue decalcification results by EDTA are good;
2. Structural damage to tissues is small;
3. Chemical testing can determine the endpoint of decalcification.

Disadvantages of EDTA decalcifying solution:
1. Decalcification rate is very slow, and not suitable for the decalcification of conventional specimens;
2. Tissue will be slightly hardened after decalcification.