Technician for Medical Laboratories Flashcards

What is the most important step in ensuring accurate patient identification before venipuncture?

Answer: Asking the patient to state their full name and date of birth

The most critical step for accurate patient identification before venipuncture is to ask the patient to verbally state their full name and date of birth. This two-factor authentication method directly involves the patient and helps prevent misidentification, ensuring the correct tests are performed on the correct individual. This is a fundamental safety practice in phlebotomy.

Which vein is most commonly used for routine venipuncture?

Answer: Median cubital vein

The median cubital vein, located in the antecubital fossa, is the most commonly used and preferred vein for routine venipuncture. It is typically large, well-anchored, and easily accessible, making it an ideal site for blood collection. Its superficial location and stability contribute to successful venipuncture.

What is the correct order of draw when using evacuated tube collection?

Answer: Blue, red, green, lavender, gray

The correct order of draw for evacuated tubes is crucial to prevent additive carryover between tubes, which could contaminate specimens and alter test results. The standard order is: blood culture (sterile), light blue (sodium citrate), red/gold/tiger top (serum), green (heparin), lavender (EDTA), and gray (fluoride/oxalate). This sequence minimizes interference with laboratory tests.

Which additive is found in the lavender-top tube and what is its function?

Answer: EDTA – prevents clotting by binding calcium

The lavender-top tube contains EDTA (ethylenediaminetetraacetic acid) as an anticoagulant. EDTA works by binding to calcium ions, which are essential cofactors in the coagulation cascade, thereby effectively preventing blood from clotting. This action preserves cellular components, making it ideal for hematology tests like complete blood counts (CBC).

What should a phlebotomy technician do if a patient begins to feel faint during a blood draw?

Answer: Instruct the patient to lie down and remove the tourniquet

Removing the tourniquet and assisting the patient to a safe position helps prevent injury from fainting during venipuncture.

Which of the following actions may lead to hemolysis of the blood sample?

Answer: Using a small bore needle

Small gauge needles can cause red blood cells to rupture due to high pressure during collection, leading to hemolysis.

Why should blood cultures be drawn first when performing multiple tests?

Answer: To avoid contamination from other tubes

Drawing blood cultures first prevents contamination from additives in other tubes, which could compromise test results.

Which of the following is considered a critical step in preventing needlestick injuries?

Answer: Disposing of the needle immediately in a sharps container

Immediate disposal of needles into a sharps container helps prevent accidental needlestick injuries and ensures safe handling.

What is the primary purpose of the tourniquet during venipuncture?

Answer: Make veins more prominent and easier to locate

A tourniquet temporarily slows venous blood flow, making the veins more visible and easier to access.

How long should pressure be applied to a venipuncture site after removing the needle?

Answer: Until bleeding stops (typically 1-2 minutes)

Pressure must be applied until bleeding ceases to prevent bruising or hematoma formation at the puncture site.

Which of the following is the correct procedure for labeling specimens?

Answer: Label the tubes at the bedside immediately after collection

Proper labeling at the point of collection reduces errors and ensures the specimen is accurately matched to the patient.