What is the primary role of the red tube in a draw?

The primary role of the red tube in a blood draw is to collect serum for various tests. This tube is typically devoid of any additives, which means that when blood is drawn into it, it will clot. After the blood has clotted, the serum can then be separated from the cellular components by centrifugation. This serum is used in a wide range of laboratory tests, including those that measure chemical levels, hormones, and proteins in the blood. Since the red tube does not contain any anticoagulants, it is specifically designed for tests that require the separation of serum after clotting, making it essential in the clinical laboratory setting.