MLPAO Specimen Collection and Procurement Questions and Answers 2

Question 1

What is the recommended angle for needle insertion during standard adult antecubital venipuncture?

Accepted Answer

15-30 degrees

Answer

The recommended needle insertion angle for venipuncture is 15-30 degrees (bevel up). This angle provides controlled entry into the vein while minimizing the risk of passing through the posterior vein wall.

Question 2

Which vein is considered the preferred primary site for adult venipuncture and why?

Accepted Answer

Median cubital vein — it is large, well-anchored, and has few nearby nerves and arteries

Answer

The median cubital vein is the preferred first-choice venipuncture site because it is typically large, well-supported by subcutaneous tissue, well-anchored, and relatively distant from major arteries and nerves.

Question 3

What action should be taken if a hematoma begins to form during venipuncture?

Accepted Answer

Immediately release the tourniquet, withdraw the needle, and apply firm pressure

Answer

Hematoma formation indicates blood is entering the tissue rather than the collection tube. The tourniquet must be released and needle withdrawn immediately, followed by firm pressure to prevent further extravasation.

Question 4

For a glucose tolerance test (GTT), a 75g oral glucose challenge is administered. When is the post-load blood specimen collected for a standard 2-hour OGTT?

Accepted Answer

120 minutes (2 hours) after glucose ingestion

Answer

The standard 2-hour OGTT (oral glucose tolerance test) requires collection of a blood specimen exactly 120 minutes (2 hours) after the patient finishes drinking the 75g glucose solution.

Question 5

What is the function of lithium heparin in a green-top blood collection tube?

Accepted Answer

It inhibits thrombin and activated factor X to prevent clotting while preserving cellular morphology

Answer

Lithium heparin is an anticoagulant that works by potentiating antithrombin III, which inhibits thrombin and factor Xa, preventing clot formation. It preserves plasma in a near-physiological state.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO Specimen Collection and Procurement Questions and Answers 2