ASCP Phlebotomy Technician Order of Draw and Additives 3

Question 1

Which anticoagulant inhibits thrombin and is used in green-topped tubes?

Accepted Answer

Heparin

Answer

Heparin (lithium or sodium) is found in green-topped tubes and works by inhibiting thrombin through activation of antithrombin III.

Question 2

What would happen if an EDTA tube were drawn before a chemistry (red/gold) tube in the order of draw?

Accepted Answer

Falsely elevated potassium and decreased calcium in the chemistry specimen

Answer

EDTA carry-over into a chemistry tube would introduce excess potassium (from K-EDTA salts) and chelate calcium, producing falsely elevated potassium and decreased calcium results.

Question 3

Royal blue-topped tubes are used for which type of testing?

Accepted Answer

Trace element and heavy metal analysis

Answer

Royal blue-topped tubes are specially manufactured for trace element and heavy metal testing because they are certified to contain no detectable amounts of these metals.

Question 4

Why is potassium oxalate paired with sodium fluoride in gray-topped tubes?

Accepted Answer

Sodium fluoride preserves glucose while potassium oxalate prevents clotting

Answer

Sodium fluoride serves as the antiglycolytic agent to preserve glucose, while potassium oxalate serves as the anticoagulant to prevent clotting.

Question 5

A lab test order requires a specimen in a tube with no additives. Which tube should the phlebotomist select?

Accepted Answer

Red glass tube (no additive)

Answer

A red glass tube (plain red top with no clot activator) contains no additives and allows blood to clot naturally.

ASCP Phlebotomy Technician Exam Practice Test

ASCP Phlebotomy Technician Exam Practice Test

ASCP Phlebotomy Technician Order of Draw and Additives 3