Final answer:
The phlebotomy technician should select a tube with EDTA additive for a CBC blood specimen.
Step-by-step explanation:
The phlebotomy technician should select a tube that has EDTA (Ethylene diamine tetra-acetic acid) additive when collecting a blood specimen for a Complete Blood Count (CBC).
EDTA is an anticoagulant that prevents blood from clotting and is commonly used for CBC tests because it preserves cellular elements and inhibits the coagulation process.
Other additives mentioned, such as SST (Serum Separator Tube), Lithium heparin, and Sodium citrate, are used for different types of blood tests and serve different purposes.