2026 PBT Exam Prep: Phlebotomy
Technician Practice Questions, Answer
Rationales, Venipuncture, Capillary
Collection, Specimen Handling, Safety &
Patient Care Study Guide
SECTION 1: CIRCULATORY SYSTEM & BLOOD COMPOSITION
(Questions 1–12)
1. A phlebotomist is reviewing the anatomy of the antecubital fossa before
performing a venipuncture. Which vein is most commonly used for routine
venipuncture because it is the largest, most stationary, and least likely to cause
complications?
A) Cephalic vein
B) Basilic vein
C) Median cubital vein
D) Median antebrachial vein
Rationale: The median cubital vein is the preferred vein for routine venipuncture.
It is the largest and most stationary vein in the antecubital fossa, and it lies between
the cephalic and basilic veins. The basilic vein is closer to the brachial artery and
the median antebrachial cutaneous nerve, increasing the risk of arterial puncture
and nerve injury. The cephalic vein is the second choice. The median antebrachial
vein is smaller and less commonly used. The ASCP PBT content outline includes
the circulatory system, specifically structure and function, as 5–10% of the exam.
2. A physician orders a complete blood count (CBC). Which blood component is
primarily evaluated by this test?
A) Plasma proteins
B) Cellular components of blood (RBCs, WBCs, platelets)
C) Clotting factors
D) Electrolytes
,Rationale: A CBC evaluates the cellular components of blood: red blood cells
(RBCs), white blood cells (WBCs), and platelets, along with related indices such
as hemoglobin and hematocrit. Plasma proteins, clotting factors, and electrolytes
are measured by other tests (e.g., comprehensive metabolic panel, coagulation
studies). The circulatory system domain includes composition and function of
blood.
3. Which of the following is the primary function of red blood cells?
A) Fight infection
B) Transport oxygen to tissues
C) Initiate blood clotting
D) Produce antibodies
Rationale: The primary function of red blood cells (erythrocytes) is to transport
oxygen from the lungs to tissues and to carry carbon dioxide back to the lungs.
White blood cells fight infection, platelets initiate hemostasis, and plasma cells
produce antibodies. This is a foundational concept in the circulatory system
domain.
4. A patient is diagnosed with mitral valve prolapse. Which valve is affected?
A) The valve between the right atrium and right ventricle
B) The valve at the exit of the right ventricle
C) The valve between the left atrium and left ventricle
D) The valve at the exit of the left ventricle
Rationale: The mitral valve (bicuspid valve) is located between the left atrium and
the left ventricle. The tricuspid valve is between the right atrium and right
ventricle. The pulmonary valve is at the exit of the right ventricle. The aortic valve
is at the exit of the left ventricle. This anatomy question is typical of the circulatory
system domain.
5. A phlebotomist is about to collect an arterial blood gas specimen and is feeling
the thumb side of the patient's wrist. Which artery is being located?
,A) Ulnar artery
B) Brachial artery
C) Radial artery
D) Femoral artery
Rationale: The radial artery is located on the thumb side (lateral aspect) of the
wrist and is the most common site for arterial blood gas collection. The ulnar artery
is on the pinky side. The brachial artery is in the antecubital fossa. The femoral
artery is in the groin. This is part of the circulatory system domain.
6. What is the primary function of white blood cells?
A) Transport oxygen
B) Defend the body against infection and foreign substances
C) Initiate clot formation
D) Carry hormones
Rationale: White blood cells (leukocytes) are the primary cells of the immune
system. They defend the body against infection, foreign substances, and abnormal
cells. Red blood cells transport oxygen, platelets initiate hemostasis, and plasma
transports hormones. This is a core circulatory system concept.
7. Which of the following describes the liquid portion of blood that remains after
clotting has occurred?
A) Plasma
B) Serum
C) Buffy coat
D) Whole blood
Rationale: Serum is the liquid portion of blood that remains after blood has clotted
and the clot has been removed. Plasma is the liquid portion of anticoagulated blood
(clotting has not occurred). The buffy coat is the layer of white blood cells and
platelets between plasma and red blood cells after centrifugation. Whole blood
contains all components. Understanding the difference between serum and plasma
is essential for tube selection.
, 8. A phlebotomist observes petechiae on a patient's arm after applying the
tourniquet. What does this finding most likely indicate?
A) The patient is extremely anemic
B) The tourniquet is tied too tightly
C) The patient has a bleeding disorder or fragile capillaries
D) The patient has high blood pressure
Rationale: Petechiae are small, pinpoint hemorrhages that appear when capillaries
rupture. Their appearance after tourniquet application suggests fragile capillaries or
a bleeding disorder (e.g., thrombocytopenia). While excessive tourniquet pressure
can cause petechiae, the finding should prompt consideration of an underlying
bleeding disorder. The venipuncture site may bleed excessively, and the
phlebotomist should be prepared with additional gauze and pressure.
9. Which blood component is primarily responsible for hemostasis (clot
formation)?
A) Red blood cells
B) White blood cells
C) Platelets
D) Plasma proteins
Rationale: Platelets (thrombocytes) are cell fragments that circulate in the blood
and are essential for primary hemostasis. When a blood vessel is injured, platelets
adhere to the site, aggregate, and form a platelet plug. Coagulation factors (plasma
proteins) then reinforce the plug with fibrin. Red blood cells transport oxygen;
white blood cells fight infection. This is foundational circulatory system
knowledge.
10. A patient's diagnosis is tricuspid valve regurgitation. This means the valve
between which two chambers is affected?
A) Left atrium and left ventricle
B) Right atrium and right ventricle
C) Right ventricle and pulmonary artery
D) Left ventricle and aorta
Technician Practice Questions, Answer
Rationales, Venipuncture, Capillary
Collection, Specimen Handling, Safety &
Patient Care Study Guide
SECTION 1: CIRCULATORY SYSTEM & BLOOD COMPOSITION
(Questions 1–12)
1. A phlebotomist is reviewing the anatomy of the antecubital fossa before
performing a venipuncture. Which vein is most commonly used for routine
venipuncture because it is the largest, most stationary, and least likely to cause
complications?
A) Cephalic vein
B) Basilic vein
C) Median cubital vein
D) Median antebrachial vein
Rationale: The median cubital vein is the preferred vein for routine venipuncture.
It is the largest and most stationary vein in the antecubital fossa, and it lies between
the cephalic and basilic veins. The basilic vein is closer to the brachial artery and
the median antebrachial cutaneous nerve, increasing the risk of arterial puncture
and nerve injury. The cephalic vein is the second choice. The median antebrachial
vein is smaller and less commonly used. The ASCP PBT content outline includes
the circulatory system, specifically structure and function, as 5–10% of the exam.
2. A physician orders a complete blood count (CBC). Which blood component is
primarily evaluated by this test?
A) Plasma proteins
B) Cellular components of blood (RBCs, WBCs, platelets)
C) Clotting factors
D) Electrolytes
,Rationale: A CBC evaluates the cellular components of blood: red blood cells
(RBCs), white blood cells (WBCs), and platelets, along with related indices such
as hemoglobin and hematocrit. Plasma proteins, clotting factors, and electrolytes
are measured by other tests (e.g., comprehensive metabolic panel, coagulation
studies). The circulatory system domain includes composition and function of
blood.
3. Which of the following is the primary function of red blood cells?
A) Fight infection
B) Transport oxygen to tissues
C) Initiate blood clotting
D) Produce antibodies
Rationale: The primary function of red blood cells (erythrocytes) is to transport
oxygen from the lungs to tissues and to carry carbon dioxide back to the lungs.
White blood cells fight infection, platelets initiate hemostasis, and plasma cells
produce antibodies. This is a foundational concept in the circulatory system
domain.
4. A patient is diagnosed with mitral valve prolapse. Which valve is affected?
A) The valve between the right atrium and right ventricle
B) The valve at the exit of the right ventricle
C) The valve between the left atrium and left ventricle
D) The valve at the exit of the left ventricle
Rationale: The mitral valve (bicuspid valve) is located between the left atrium and
the left ventricle. The tricuspid valve is between the right atrium and right
ventricle. The pulmonary valve is at the exit of the right ventricle. The aortic valve
is at the exit of the left ventricle. This anatomy question is typical of the circulatory
system domain.
5. A phlebotomist is about to collect an arterial blood gas specimen and is feeling
the thumb side of the patient's wrist. Which artery is being located?
,A) Ulnar artery
B) Brachial artery
C) Radial artery
D) Femoral artery
Rationale: The radial artery is located on the thumb side (lateral aspect) of the
wrist and is the most common site for arterial blood gas collection. The ulnar artery
is on the pinky side. The brachial artery is in the antecubital fossa. The femoral
artery is in the groin. This is part of the circulatory system domain.
6. What is the primary function of white blood cells?
A) Transport oxygen
B) Defend the body against infection and foreign substances
C) Initiate clot formation
D) Carry hormones
Rationale: White blood cells (leukocytes) are the primary cells of the immune
system. They defend the body against infection, foreign substances, and abnormal
cells. Red blood cells transport oxygen, platelets initiate hemostasis, and plasma
transports hormones. This is a core circulatory system concept.
7. Which of the following describes the liquid portion of blood that remains after
clotting has occurred?
A) Plasma
B) Serum
C) Buffy coat
D) Whole blood
Rationale: Serum is the liquid portion of blood that remains after blood has clotted
and the clot has been removed. Plasma is the liquid portion of anticoagulated blood
(clotting has not occurred). The buffy coat is the layer of white blood cells and
platelets between plasma and red blood cells after centrifugation. Whole blood
contains all components. Understanding the difference between serum and plasma
is essential for tube selection.
, 8. A phlebotomist observes petechiae on a patient's arm after applying the
tourniquet. What does this finding most likely indicate?
A) The patient is extremely anemic
B) The tourniquet is tied too tightly
C) The patient has a bleeding disorder or fragile capillaries
D) The patient has high blood pressure
Rationale: Petechiae are small, pinpoint hemorrhages that appear when capillaries
rupture. Their appearance after tourniquet application suggests fragile capillaries or
a bleeding disorder (e.g., thrombocytopenia). While excessive tourniquet pressure
can cause petechiae, the finding should prompt consideration of an underlying
bleeding disorder. The venipuncture site may bleed excessively, and the
phlebotomist should be prepared with additional gauze and pressure.
9. Which blood component is primarily responsible for hemostasis (clot
formation)?
A) Red blood cells
B) White blood cells
C) Platelets
D) Plasma proteins
Rationale: Platelets (thrombocytes) are cell fragments that circulate in the blood
and are essential for primary hemostasis. When a blood vessel is injured, platelets
adhere to the site, aggregate, and form a platelet plug. Coagulation factors (plasma
proteins) then reinforce the plug with fibrin. Red blood cells transport oxygen;
white blood cells fight infection. This is foundational circulatory system
knowledge.
10. A patient's diagnosis is tricuspid valve regurgitation. This means the valve
between which two chambers is affected?
A) Left atrium and left ventricle
B) Right atrium and right ventricle
C) Right ventricle and pulmonary artery
D) Left ventricle and aorta
