NCCT Equipment, Tubes, and Additives 3

Question 1

In the correct order of draw for evacuated tubes, which tube is collected first?

Accepted Answer

Blood culture bottles

Answer

Blood culture bottles are always drawn first because they require the most sterile specimen, and any additive carryover from other tubes could affect microbial growth.

Question 2

What additive is found in green-top evacuated tubes?

Accepted Answer

Heparin (lithium or sodium)

Answer

Green-top tubes contain heparin (lithium heparin, sodium heparin, or ammonium heparin), an anticoagulant used for chemistry testing on plasma.

Question 3

Why must a light blue-top tube be completely filled to the indicated mark?

Accepted Answer

To maintain the correct 9:1 blood-to-anticoagulant ratio

Answer

Sodium citrate tubes require a precise 9:1 ratio of blood to anticoagulant. Underfilling alters this ratio, causing inaccurate coagulation test results.

Question 4

What is the purpose of clot activator in a red/gold-top tube?

Accepted Answer

To accelerate clot formation for faster serum separation

Answer

Clot activators (silica particles or glass) accelerate the coagulation process so serum can be separated from the clot more quickly.

Question 5

A phlebotomist needs to collect a specimen for trace metal analysis. Which tube should be used?

Accepted Answer

Royal blue-top tube with EDTA

Answer

Royal blue-top tubes are specially manufactured with trace-element-free materials to prevent contamination of specimens for trace metal analysis.

NCCT - National Certified Phlebotomy Technician Exam Practice Test

NCCT - National Certified Phlebotomy Technician Exam Practice Test

NCCT Equipment, Tubes, and Additives 3