NHI Phlebotomy and Lab Procedures 2

Question 1

Which additive in a lavender-top tube prevents clotting by binding calcium?

Accepted Answer

EDTA

Answer

EDTA (ethylenediaminetetraacetic acid) chelates calcium ions to prevent coagulation in lavender-top tubes.

Question 2

A patient's arm shows a hematoma forming during venipuncture. What is the FIRST action?

Accepted Answer

Release the tourniquet and remove the needle

Answer

When a hematoma forms, the phlebotomist must immediately release the tourniquet and remove the needle to stop blood from leaking into surrounding tissue.

Question 3

Which vein is considered the FIRST choice for routine venipuncture in adults?

Accepted Answer

Median cubital vein

Answer

The median cubital vein is preferred because it is large, well-anchored, and usually close to the surface with minimal nerves nearby.

Question 4

What is the purpose of the 'order of draw' in phlebotomy?

Accepted Answer

To prevent cross-contamination of additives between tubes

Answer

The order of draw minimizes carryover of tube additives into subsequent tubes, which could interfere with test results.

Question 5

A gray-top tube contains sodium fluoride. What is its PRIMARY purpose?

Accepted Answer

Inhibit glycolysis to preserve glucose levels

Answer

Sodium fluoride inhibits glycolytic enzymes, preventing red blood cells from consuming glucose and ensuring accurate glucose measurements.

(NHI) National Healthcareer Institute Certification Practice Test

(NHI) National Healthcareer Institute Certification Practice Test

NHI Phlebotomy and Lab Procedures 2