Spring Semester 2026 Phlebotomy Technician Certification
Practice Questions and Answers | Complete Certified Phlebotomy
Technician (CPT) Study Guide with Verified Questions, Detailed
Rationales, Venipuncture Techniques, Capillary Blood Collection,
Order of Draw, Specimen Handling, Infection Control, Patient
Identification, Laboratory Safety, Quality Assurance & Phlebotomy
Exam Prep
Question 1: Which of the following is the primary purpose of applying a tourniquet
during venipuncture?
A. To sterilize the puncture site
B. To restrict arterial blood flow
C. To engorge veins by restricting venous return
D. To numb the area before needle insertion
CORRECT ANSWER: C. To engorge veins by restricting venous return
Rationale: The tourniquet is applied to restrict venous blood flow back to the heart,
causing the veins to fill with blood and become more prominent (engorged), which
makes them easier to locate and access. It should not restrict arterial flow, as this
would cause pallor and pain.
Question 2: What is the recommended maximum time a tourniquet should remain
applied during a venipuncture procedure?
A. 30 seconds
B. 1 minute
C. 3 minutes
D. 5 minutes
CORRECT ANSWER: B. 1 minute
Rationale: A tourniquet should not be left on for longer than one minute. Prolonged
application can cause hemoconcentration, leading to falsely elevated levels of certain
analytes such as potassium, lactate, and proteins.
Question 3: Which gauge needle is most commonly used for routine adult
venipuncture?
A. 18-gauge
B. 21-gauge
C. 25-gauge
D. 30-gauge
CORRECT ANSWER: B. 21-gauge
Rationale: A 21-gauge needle is the standard size for routine adult venipuncture. It
provides a good balance between patient comfort and efficient blood flow. An 18-gauge
,is typically used for blood donation, while 23-25 gauge needles are often used for
pediatric or geriatric patients with fragile veins.
Question 4: When performing a capillary puncture on an infant, which site is
preferred?
A. The tip of the index finger
B. The medial aspect of the heel
C. The earlobe
D. The antecubital fossa
CORRECT ANSWER: B. The medial aspect of the heel
Rationale: For infants under 12 months old, the medial or lateral plantar surface of the
heel is the preferred site for capillary puncture. Fingersticks are generally reserved for
older children and adults to avoid damage to the bone and nerves in the heel.
Question 5: Which tube additive is found in a lavender-top tube?
A. Sodium citrate
B. Heparin
C. Ethylenediaminetetraacetic acid (EDTA)
D. Potassium oxalate
CORRECT ANSWER: C. Ethylenediaminetetraacetic acid (EDTA)
Rationale: Lavender-top tubes contain EDTA, which acts as an anticoagulant by
chelating calcium. These tubes are primarily used for hematology tests, such as the
Complete Blood Count (CBC).
Question 6: What is the correct order of draw for the following tubes: Light Blue,
Red, Green, and Lavender?
A. Red, Light Blue, Green, Lavender
B. Light Blue, Red, Green, Lavender
C. Lavender, Green, Red, Light Blue
D. Green, Light Blue, Lavender, Red
CORRECT ANSWER: B. Light Blue, Red, Green, Lavender
Rationale: The standard order of draw minimizes cross-contamination of additives.
Light blue (citrate) comes first to ensure accurate coagulation studies. Serum tubes
(Red) follow, then heparin (Green), and finally EDTA (Lavender).
Question 7: Why must a light blue-top tube be filled to its stated volume?
A. To prevent hemolysis
B. To maintain the correct ratio of blood to anticoagulant
C. To ensure the vacuum is exhausted
D. To allow for proper mixing with the clot activator
,CORRECT ANSWER: B. To maintain the correct ratio of blood to anticoagulant
Rationale: Light blue-top tubes contain sodium citrate, which requires a specific 9:1
ratio of blood to anticoagulant. Underfilling the tube results in excess citrate, which can
falsely prolong coagulation times (PT/PTT).
Question 8: Which of the following is a sign of hemolysis in a blood sample?
A. The serum appears clear and yellow
B. The plasma appears pink or red
C. The sample has a high lipid content
D. The sample contains small clots
CORRECT ANSWER: B. The plasma appears pink or red
Rationale: Hemolysis is the rupture of red blood cells, releasing hemoglobin into the
plasma or serum. This causes the liquid portion of the sample to appear pink or red
rather than clear straw-colored. Hemolyzed samples are often rejected because
intracellular components like potassium can leak out, skewing test results.
Question 9: What is the primary reason for inverting additive tubes after collection?
A. To mix the blood with the additive thoroughly
B. To activate the clotting process
C. To release the vacuum in the tube
D. To cool the sample down
CORRECT ANSWER: A. To mix the blood with the additive thoroughly
Rationale: Additive tubes must be inverted gently immediately after collection to
ensure the additive mixes completely with the blood. Failure to mix can result in
microclots forming (in anticoagulant tubes) or incomplete separation of serum.
Question 10: Which vein is considered the first choice for venipuncture in the
antecubital fossa?
A. Basilic vein
B. Cephalic vein
C. Median cubital vein
D. Dorsal metacarpal vein
CORRECT ANSWER: C. Median cubital vein
Rationale: The median cubital vein is located in the center of the antecubital fossa. It is
typically large, well-anchored, and less painful to access because it lies over fewer
nerve endings compared to the basilic or cephalic veins.
Question 11: What is the appropriate action if a patient faints (syncope) during a
blood draw?
, A. Continue the draw quickly to finish
B. Remove the needle, lower the patient’s head, and call for help
C. Shake the patient to wake them up
D. Apply ice to the patient’s forehead
CORRECT ANSWER: B. Remove the needle, lower the patient’s head, and call for
help
Rationale: Patient safety is the priority. The needle must be removed immediately to
prevent injury if the patient jerks or falls. Lowering the head helps restore blood flow to
the brain. Emergency assistance should be summoned if the patient does not recover
quickly.
Question 12: Which personal protective equipment (PPE) is mandatory for a
phlebotomist during every blood collection?
A. Gown and face shield
B. Gloves
C. N95 respirator
D. Shoe covers
CORRECT ANSWER: B. Gloves
Rationale: According to Standard Precautions, gloves must be worn during all
procedures involving contact with blood or body fluids to protect both the healthcare
worker and the patient from potential infection. Other PPE is used based on specific risk
assessments.
Question 13: What is the correct angle of insertion for a standard venipuncture
using an evacuated tube system?
A. 5 to 10 degrees
B. 15 to 30 degrees
C. 45 to 60 degrees
D. 90 degrees
CORRECT ANSWER: B. 15 to 30 degrees
Rationale: The needle should be inserted at a 15 to 30-degree angle with the bevel up.
Angles that are too shallow may result in missing the vein or going through the top wall,
while angles that are too steep may go through the bottom wall of the vein.
Question 14: Which test requires strict protection from light after collection?
A. Glucose
B. Bilirubin
C. Cholesterol
D. Urea Nitrogen
CORRECT ANSWER: B. Bilirubin
Practice Questions and Answers | Complete Certified Phlebotomy
Technician (CPT) Study Guide with Verified Questions, Detailed
Rationales, Venipuncture Techniques, Capillary Blood Collection,
Order of Draw, Specimen Handling, Infection Control, Patient
Identification, Laboratory Safety, Quality Assurance & Phlebotomy
Exam Prep
Question 1: Which of the following is the primary purpose of applying a tourniquet
during venipuncture?
A. To sterilize the puncture site
B. To restrict arterial blood flow
C. To engorge veins by restricting venous return
D. To numb the area before needle insertion
CORRECT ANSWER: C. To engorge veins by restricting venous return
Rationale: The tourniquet is applied to restrict venous blood flow back to the heart,
causing the veins to fill with blood and become more prominent (engorged), which
makes them easier to locate and access. It should not restrict arterial flow, as this
would cause pallor and pain.
Question 2: What is the recommended maximum time a tourniquet should remain
applied during a venipuncture procedure?
A. 30 seconds
B. 1 minute
C. 3 minutes
D. 5 minutes
CORRECT ANSWER: B. 1 minute
Rationale: A tourniquet should not be left on for longer than one minute. Prolonged
application can cause hemoconcentration, leading to falsely elevated levels of certain
analytes such as potassium, lactate, and proteins.
Question 3: Which gauge needle is most commonly used for routine adult
venipuncture?
A. 18-gauge
B. 21-gauge
C. 25-gauge
D. 30-gauge
CORRECT ANSWER: B. 21-gauge
Rationale: A 21-gauge needle is the standard size for routine adult venipuncture. It
provides a good balance between patient comfort and efficient blood flow. An 18-gauge
,is typically used for blood donation, while 23-25 gauge needles are often used for
pediatric or geriatric patients with fragile veins.
Question 4: When performing a capillary puncture on an infant, which site is
preferred?
A. The tip of the index finger
B. The medial aspect of the heel
C. The earlobe
D. The antecubital fossa
CORRECT ANSWER: B. The medial aspect of the heel
Rationale: For infants under 12 months old, the medial or lateral plantar surface of the
heel is the preferred site for capillary puncture. Fingersticks are generally reserved for
older children and adults to avoid damage to the bone and nerves in the heel.
Question 5: Which tube additive is found in a lavender-top tube?
A. Sodium citrate
B. Heparin
C. Ethylenediaminetetraacetic acid (EDTA)
D. Potassium oxalate
CORRECT ANSWER: C. Ethylenediaminetetraacetic acid (EDTA)
Rationale: Lavender-top tubes contain EDTA, which acts as an anticoagulant by
chelating calcium. These tubes are primarily used for hematology tests, such as the
Complete Blood Count (CBC).
Question 6: What is the correct order of draw for the following tubes: Light Blue,
Red, Green, and Lavender?
A. Red, Light Blue, Green, Lavender
B. Light Blue, Red, Green, Lavender
C. Lavender, Green, Red, Light Blue
D. Green, Light Blue, Lavender, Red
CORRECT ANSWER: B. Light Blue, Red, Green, Lavender
Rationale: The standard order of draw minimizes cross-contamination of additives.
Light blue (citrate) comes first to ensure accurate coagulation studies. Serum tubes
(Red) follow, then heparin (Green), and finally EDTA (Lavender).
Question 7: Why must a light blue-top tube be filled to its stated volume?
A. To prevent hemolysis
B. To maintain the correct ratio of blood to anticoagulant
C. To ensure the vacuum is exhausted
D. To allow for proper mixing with the clot activator
,CORRECT ANSWER: B. To maintain the correct ratio of blood to anticoagulant
Rationale: Light blue-top tubes contain sodium citrate, which requires a specific 9:1
ratio of blood to anticoagulant. Underfilling the tube results in excess citrate, which can
falsely prolong coagulation times (PT/PTT).
Question 8: Which of the following is a sign of hemolysis in a blood sample?
A. The serum appears clear and yellow
B. The plasma appears pink or red
C. The sample has a high lipid content
D. The sample contains small clots
CORRECT ANSWER: B. The plasma appears pink or red
Rationale: Hemolysis is the rupture of red blood cells, releasing hemoglobin into the
plasma or serum. This causes the liquid portion of the sample to appear pink or red
rather than clear straw-colored. Hemolyzed samples are often rejected because
intracellular components like potassium can leak out, skewing test results.
Question 9: What is the primary reason for inverting additive tubes after collection?
A. To mix the blood with the additive thoroughly
B. To activate the clotting process
C. To release the vacuum in the tube
D. To cool the sample down
CORRECT ANSWER: A. To mix the blood with the additive thoroughly
Rationale: Additive tubes must be inverted gently immediately after collection to
ensure the additive mixes completely with the blood. Failure to mix can result in
microclots forming (in anticoagulant tubes) or incomplete separation of serum.
Question 10: Which vein is considered the first choice for venipuncture in the
antecubital fossa?
A. Basilic vein
B. Cephalic vein
C. Median cubital vein
D. Dorsal metacarpal vein
CORRECT ANSWER: C. Median cubital vein
Rationale: The median cubital vein is located in the center of the antecubital fossa. It is
typically large, well-anchored, and less painful to access because it lies over fewer
nerve endings compared to the basilic or cephalic veins.
Question 11: What is the appropriate action if a patient faints (syncope) during a
blood draw?
, A. Continue the draw quickly to finish
B. Remove the needle, lower the patient’s head, and call for help
C. Shake the patient to wake them up
D. Apply ice to the patient’s forehead
CORRECT ANSWER: B. Remove the needle, lower the patient’s head, and call for
help
Rationale: Patient safety is the priority. The needle must be removed immediately to
prevent injury if the patient jerks or falls. Lowering the head helps restore blood flow to
the brain. Emergency assistance should be summoned if the patient does not recover
quickly.
Question 12: Which personal protective equipment (PPE) is mandatory for a
phlebotomist during every blood collection?
A. Gown and face shield
B. Gloves
C. N95 respirator
D. Shoe covers
CORRECT ANSWER: B. Gloves
Rationale: According to Standard Precautions, gloves must be worn during all
procedures involving contact with blood or body fluids to protect both the healthcare
worker and the patient from potential infection. Other PPE is used based on specific risk
assessments.
Question 13: What is the correct angle of insertion for a standard venipuncture
using an evacuated tube system?
A. 5 to 10 degrees
B. 15 to 30 degrees
C. 45 to 60 degrees
D. 90 degrees
CORRECT ANSWER: B. 15 to 30 degrees
Rationale: The needle should be inserted at a 15 to 30-degree angle with the bevel up.
Angles that are too shallow may result in missing the vein or going through the top wall,
while angles that are too steep may go through the bottom wall of the vein.
Question 14: Which test requires strict protection from light after collection?
A. Glucose
B. Bilirubin
C. Cholesterol
D. Urea Nitrogen
CORRECT ANSWER: B. Bilirubin
