Which blood collection tube is most commonly used for coagulation studies?

The light blue top tube is specifically designed for coagulation studies because it contains sodium citrate as an anticoagulant. This additive binds calcium in the blood, which is essential for the coagulation process. By inhibiting calcium, the tube ensures that the blood remains in a liquid state, allowing accurate measurement of coagulation factors such as prothrombin time (PT) and activated partial thromboplastin time (aPTT).

The use of the light blue tube is critical in obtaining reliable results for these tests, as other additives could interfere with the coagulation process and lead to inaccurate results. The type of anticoagulant used, along with the specific ratio of blood to anticoagulant in the tube, is crucial for the performance of coagulation tests, making the light blue top tube the preferred choice in clinical practice.