Question

How does EDTA prevent blood samples from clotting? How does removing calcium from the sample keep it from clotting?

Answer 1

Hint: The full form of EDTA is ethylenediaminetetraacetic acid which is a solid and white-colored substance and is also widely used as a chelating agent for different ions.

Complete answer:
1)The blood does not clot inside the body due to the presence of different natural anticoagulants that prevent the clotting of blood but the blood can easily clot outside the body if the anticoagulants are not added to them.
2)Blood clotting is an overall complex process that involves different enzymes and different reactions and the calcium ion in the blood also plays a great role in the clotting of blood.
3)The EDTA is a hexadentate ligand and it can easily bind with the calcium ions that prevent the clotting of the blood even outside the body. This binding ability of EDTA makes it one of the most powerful and the most used anticoagulant and a chelating agent.
4)Hence the chelating ability of EDTA prevents the blood samples from clotting by binding to the calcium ions present in the blood samples.

Note: In hematology labs EDTA is very important and it is widely used in labs to prevent clotting of the blood samples and the EDTA used in the labs are found in two different varieties, one is known as the versene and the other is known as the sequestrene. The versene form is also known as the disodium EDTA salt and the sequestrene form is also known as the dipotassium EDTA salt.