What is the sixth tube in the order of draw?

The correct answer is the gold/tiger/marble tube, which is the sixth in the order of draw. This tube is typically used for serological tests and chemistry analyses because it contains a gel separator that helps to separate the serum from the blood cells after centrifugation. This property allows for easier handling and more accurate results for various tests, making it a crucial part of laboratory protocols.

Understanding the order of draw is vital in phlebotomy to prevent cross-contamination between different additives present in the tubes. Each type of tube has specific additives that serve different purposes, and using them in the correct order helps ensure valid test results.

In this context, while the pink tube is often used for blood banking and transfusion purposes, the dark green tube is associated with tests that require heparin as an anticoagulant, and the light green tube generally contains a lithium heparin and gel for plasma separation. None of these tubes precede the gold/tiger/marble tube in the established order, which begins with the sterile culture tubes and ends with serum tubes like the gold/tiger/marble option.