What is the primary function of Ethylenediaminetetraacetic acid (EDTA)?

Ethylenediaminetetraacetic acid (EDTA) is primarily used as an anticoagulant in blood collection. This means it effectively prevents blood from clotting when it is drawn, allowing for accurate laboratory testing of blood samples. EDTA works by chelating calcium ions, which are essential for the clotting process. By binding to these ions, EDTA interrupts the coagulation cascade, thereby maintaining the liquid state of the blood sample.

While EDTA can have some preservative effects on certain blood components, its main role in phlebotomy is to ensure the blood remains unclotted throughout processing and analysis. This is critical for tests that require a liquid specimen and where any clotting would yield inaccurate results.