Which additive is found in a light blue tube?

The light blue tube contains sodium citrate as its additive. Sodium citrate acts as an anticoagulant, which means it helps prevent blood from clotting during processing and testing. It achieves this by binding calcium ions, which are essential for the coagulation process. The use of sodium citrate is particularly important for coagulation tests, such as prothrombin time (PT) and activated partial thromboplastin time (aPTT), as these tests require the blood to remain in a liquid state to accurately assess clotting function.

This choice is crucial for ensuring the validity of coagulation test results. Each of the other additives serves different purposes; for example, heparin is an anticoagulant used in green-top tubes for plasma collection, EDTA is an anticoagulant found in lavender tubes used primarily for hematological tests, and silica is a clot activator in red top tubes, which aids in allowing blood to clot for serum collection. Understanding the role of sodium citrate and its specific application in laboratory testing is essential for phlebotomists and clinical practitioners.