CMT Laboratory Procedures and Specimen Collection

Question 1

Which evacuated tube color is used for coagulation studies such as PT and PTT?

Accepted Answer

Light blue

Answer

Light blue (sodium citrate) tubes are used for coagulation studies because citrate binds calcium to prevent clotting while preserving clotting factor activity.

Question 2

According to the CLSI order of draw, which tube should be collected FIRST when multiple tubes are needed?

Accepted Answer

Blood culture bottles

Answer

Blood culture bottles are drawn first to minimize the risk of contamination from skin flora and additives in other tubes.

Question 3

A tourniquet should be applied no longer than how many minutes before venipuncture to prevent hemoconcentration?

Accepted Answer

1 minute

Answer

A tourniquet left on longer than 1 minute causes hemoconcentration and falsely elevated results for proteins, enzymes, and cellular components.

Question 4

Which of the following actions is the MOST common cause of hemolysis during venipuncture?

Accepted Answer

Mixing tubes too vigorously

Answer

Vigorous mixing of tubes breaks red blood cell membranes, releasing intracellular contents and causing hemolysis that can interfere with test results.

Question 5

A capillary puncture on an adult finger should be performed on which part of the fingertip?

Accepted Answer

Side of the middle or ring finger

Answer

The lateral (side) aspect of the middle or ring finger is the preferred site because it has adequate capillary beds and avoids nerves and bone centrally located in the fingertip.

(CMT) Certified Medical Technician Practice Test

(CMT) Certified Medical Technician Practice Test

CMT Laboratory Procedures and Specimen Collection