Phlebotomy Training Specialists Practice Test

The dark green top tube is used primarily for tests requiring plasma because it contains a sodium heparin anticoagulant, which prevents blood from clotting. This is essential for obtaining plasma, which is the liquid part of the blood that remains after coagulation. When blood is collected in a tube with sodium heparin, it can be spun in a centrifuge to separate the plasma from the cellular components, allowing for accurate analysis of plasma constituents. In contrast, other tubes listed serve different purposes. The pink top tube typically contains EDTA, which is mainly used for blood typing and crossmatching rather than for routine plasma tests. The lavender top tube, also containing EDTA, is used primarily for hematology tests such as complete blood counts. The red top tube lacks any anticoagulants, leading to serum production after clotting, which makes it unsuitable for plasma testing. Understanding the specific additives in each tube and their intended use is crucial in phlebotomy to ensure appropriate specimen collection for laboratory analysis.