What is the primary purpose of a light blue tube in blood collection?

The primary purpose of a light blue tube in blood collection is for coagulation tests. This type of tube contains sodium citrate as an anticoagulant, which helps prevent the blood from clotting during the testing process. By doing so, it preserves the integrity of the blood sample for accurate measurement of clotting factors.

When blood is drawn into a light blue tube, the sodium citrate binds to calcium in the sample, which is essential for the clotting process. Therefore, this tube is specifically designed to ensure reliable results for tests such as prothrombin time (PT) and activated partial thromboplastin time (aPTT), both of which are crucial in evaluating the blood’s ability to clot properly and monitoring patients on anticoagulant therapy.

Understanding the specific use of the light blue tube helps phlebotomists follow the correct order of draw and ensures that samples are not compromised by improper collection techniques or tube selection.