CPHT Order of Draw & Tube Additives

Question 1

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

Accepted Answer

EDTA (ethylenediaminetetraacetic acid)

Answer

Sodium citrate

Answer

Sodium heparin

Answer

Sodium fluoride

Question 2

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

Accepted Answer

Light blue top (sodium citrate)

Answer

Green top (heparin)

Answer

Red top (no additive)

Answer

Gray top (fluoride/oxalate)

Question 3

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

Accepted Answer

Inhibit glycolysis to preserve glucose levels

Answer

Prevent clotting by chelating calcium

Answer

Preserve cell morphology for differentials

Answer

Promote rapid clot formation

Question 4

Which anticoagulant is contained in a green top tube?

Accepted Answer

Heparin

Answer

EDTA

Answer

Sodium citrate

Answer

Thrombin

Question 5

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

Accepted Answer

Clot activator and gel separator

Answer

EDTA and gel separator

Answer

Heparin and gel separator

Answer

Sodium citrate and gel separator

Question 6

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

Accepted Answer

Pink EDTA tube

Answer

Lavender/purple EDTA tube

Answer

Plain red tube (no additive)

Answer

Yellow ACD tube

Question 7

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

Accepted Answer

Trace elements and toxicology studies

Answer

Routine blood cultures

Answer

Standard coagulation panels

Answer

Routine blood typing