NHI Phlebotomy and Lab Procedures 5

Question 1

Which tube additive is found in a green-top tube and is used for plasma chemistry tests?

Accepted Answer

Heparin

Answer

Green-top tubes contain heparin (lithium or sodium heparin), which inhibits thrombin and is used when plasma is needed for chemistry testing.

Question 2

What is the MAXIMUM recommended time a tourniquet should remain applied during venipuncture?

Accepted Answer

1 minute

Answer

Tourniquets should not remain applied for more than 1 minute to prevent hemoconcentration and alteration of analyte levels.

Question 3

A patient has an IV line running in the left antecubital fossa. Where should the phlebotomist collect blood?

Accepted Answer

From the right arm or a site distal to the IV in the same arm

Answer

Blood should be drawn from the opposite arm or distal to the IV to avoid IV fluid contamination of the specimen.

Question 4

When collecting a specimen for a PKU (phenylketonuria) neonatal screen, what collection method is used?

Accepted Answer

Heel stick onto a filter paper card

Answer

Neonatal PKU screens use capillary blood from a heel stick applied directly to specific circles on a filter paper (Guthrie card).

Question 5

What term describes the clear, yellowish fluid that remains after blood has clotted and the clot is removed?

Accepted Answer

Serum

Answer

Serum is the liquid portion of blood after clotting; unlike plasma, it lacks fibrinogen and other clotting factors consumed in the clot.

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