What is the main purpose of using Lithium heparin in phlebotomy?

Lithium heparin is primarily used as an anticoagulant in phlebotomy, which means its main purpose is to prevent blood from coagulating. When blood is drawn into a tube containing lithium heparin, it inhibits the action of clotting factors, allowing for the collection of liquid plasma without the formation of a clot. This property is particularly valuable in laboratory testing, as it enables a more accurate analysis of various blood parameters by ensuring that the sample remains in a liquid state, free from clotted material.

While there might be options that relate to other functions such as preservation of blood for transfusions or enhancing test accuracy, these do not specifically define the role of lithium heparin in regard to its anticoagulant properties. Additionally, the separation of plasma from serum involves different procedures and components entirely, with serum being the liquid that remains after blood has clotted. Thus, the primary and correct use of lithium heparin in phlebotomy is to prevent coagulation.