Order of Draw & Tube Additives Flashcards

What additive is found in a lavender/purple top collection tube?

Answer: EDTA (ethylenediaminetetraacetic acid)

Lavender/purple top tubes contain EDTA, an anticoagulant that chelates calcium to prevent clotting and preserve cell morphology for hematology testing.

Which tube color is specifically used for coagulation studies such as PT/INR and aPTT?

Answer: Light blue top (sodium citrate)

Light blue top tubes contain sodium citrate, which reversibly binds calcium to prevent clotting while allowing coagulation testing through calcium re-addition.

What is the primary purpose of sodium fluoride in a gray top collection tube?

Answer: Inhibit glycolysis to preserve glucose levels

Sodium fluoride inhibits the glycolytic enzyme enolase, stopping red blood cells from metabolizing glucose and preserving accurate glucose and lactate levels.

Which anticoagulant is contained in a green top tube?

Answer: Heparin

Green top tubes contain heparin (typically lithium heparin or sodium heparin), which enhances antithrombin III activity to prevent blood clotting.

What does a gold top SST (Serum Separator Tube) contain?

Answer: Clot activator and gel separator

Gold SST tubes contain silica particles as a clot activator and a polyester gel separator that migrates between serum and clot during centrifugation.

Which tube color is specifically designated for blood bank (type and screen/crossmatch) testing?

Answer: Pink EDTA tube

Pink top tubes contain EDTA and are specially designated for blood bank testing with strict labeling requirements to ensure patient safety during transfusion.

Royal blue top tubes are primarily used for which type of testing?

Answer: Trace elements and toxicology studies

Royal blue top tubes are constructed with low-contamination materials to prevent trace metal interference, making them essential for trace element, toxicology, and nutritional testing.