Final answer:
An orange top tube in phlebotomy contains thrombin-based clot activators, used for blood tests requiring quick serum separation such as stat serum chemistry tests and therapeutic drug monitoring.
Step-by-step explanation:
In phlebotomy, an orange top tube typically contains a rapid serum tube with a clot activator. It is used for a variety of blood tests that require serum for the analysis. The additives in an orange top tube are thrombin-based clot activators, which aid in the clotting process and allow for the quick preparation of the serum sample. Tests commonly performed with orange top tubes include those that require immediate serum separation, like stat serum chemistry tests, therapeutic drug monitoring, stat electrolytes, and some immunology tests that need prompt processing.