Hematology MCQs with Answer and Explanations | Chapter 2

Answer: Condenser

The condenser is positioned beneath the stage of a microscope and is responsible for focusing and directing light onto the specimen. It collects light from the microscope’s light source (often the illuminator or light bulb), organizes it into a concentrated beam, and directs it up through the specimen on the slide. Proper adjustment of the condenser is essential for achieving good contrast and visibility in microscopy. The other components mentioned (ocular, objective lens, and optical tube) play important roles in magnification and viewing the specimen but do not primarily handle the focusing and directing of light.

Answer: Inattention during removal of needle after venipuncture

Needlestick injuries, which occur when healthcare workers accidentally puncture themselves with needles, are often a result of inattention or carelessness during the removal of the needle after venipuncture. These injuries can lead to the transmission of bloodborne pathogens and are a significant concern in healthcare settings. Proper training, safe needle disposal, and adherence to safety protocols are crucial in preventing needlestick injuries and protecting healthcare workers and patients from potential infections.

Answer: >95% Hb A, <3.5 % Hb A2, <1-2% Hb F

This distribution reflects the predominant types of hemoglobin found in adults. Hb A is the most common, making up more than 95% of the total hemoglobin. Hb A2 and Hb F are present in smaller percentages, as indicated in the distribution.

Answer: Pyruvate Kinase

Pyruvate kinase is a critical enzyme in the glycolysis pathway, which is a part of the Embden-Meyerhof pathway. In the context of hemolysis, a deficiency of pyruvate kinase results in a decreased ability of red blood cells to produce ATP (adenosine triphosphate) through glycolysis. This leads to the accumulation of intermediates in the pathway and causes red blood cells to become more fragile, leading to hemolysis (rupture of red blood cells). As a result, pyruvate kinase deficiency is associated with nonspherocytic hemolytic anemia.

Answer: High WBC

Cryofibrinogen is a term used to describe abnormal proteins in the blood that can precipitate at low temperatures. When cryofibrinogen is present, it can cause clumping or agglutination of red blood cells in the sample, leading to a falsely decreased MCV measurement in a complete blood count (CBC). Hyperglycemia, autoagglutination, and high white blood cell count (WBC) can also have various effects on laboratory test results, but they are not typically associated with a spurious decrease in MCV.

Answer: Liver

In the early stages of fetal development, blood cells are formed in the yolk sac. However, during midfetal life, the liver becomes the primary site for hematopoiesis, or blood cell production. The liver produces red blood cells and other blood cell types, and it continues to serve as a significant hematopoietic organ until the bone marrow takes over this role in the later stages of fetal development and postnatally. The spleen and lymph nodes are involved in immune functions and not the primary sites of blood cell production.

Answer: MCV

MCV measures the average volume of a single red blood cell and is expressed in femtoliters (fl). It provides information about the size of the red blood cells, with values outside the reference range indicating microcytic (small), normocytic (normal), or macrocytic (large) RBCs. MCH (Mean Corpuscular Hemoglobin) measures the average weight of hemoglobin in a single RBC, and MCHC (Mean Corpuscular Hemoglobin Concentration) assesses the concentration of hemoglobin in RBCs.

Answer: Clopidogrel and Ticlopidine

• Sulfinpyrazone is a uricosuric agent that can cause hypersensitivity reactions in patients with aspirin sensitivity.
• Clopidogrel and ticlopidine are thienopyridine antiplatelet agents that are generally safe for patients with aspirin sensitivity.

Therefore, patients with aspirin sensitivity can take clopidogrel and ticlopidine, but not sulfinpyrazone.

Answer: Lymphocyte

• Lymphocytes are a type of white blood cell that are responsible for the body’s immune response. They are produced in the bone marrow, but they can also mature and develop in other lymphoid tissues, such as the thymus, spleen, and lymph nodes.
• Monocytes, megakaryocytes, and neutrophils are all produced and mature in the bone marrow. They do not typically develop in other sites.

Therefore, the only cell listed that may develop in sites other than the bone marrow is the lymphocyte.

Answer: 70 % alcohol or lens cleaner

Using 70% isopropyl alcohol (or ethanol) is a common and safe method for cleaning objective lenses in microscopy. It helps to remove oil, fingerprints, and other contaminants without damaging the lens or optical coatings. Alternatively, you can use a lens cleaner specifically designed for optics, which is often available as a cleaning solution or wipes.

Xylene, benzene, and water are not typically recommended for cleaning objective lenses. Xylene and benzene are strong organic solvents that can damage optics and should be avoided. Water is not recommended because it can leave residue and may not effectively remove oil and other substances.

Answer: White blood cells

White blood cells play a key role in the immune response. White blood cells, also known as leukocytes, are an essential part of the body’s immune system. They help protect the body against infections, bacteria, viruses, and other foreign invaders. While red blood cells are primarily responsible for oxygen transport, white blood cells are responsible for defending the body against pathogens and contributing to the immune response. Platelets are involved in blood clotting, and plasma is the liquid component of blood that carries blood cells and various substances, including antibodies produced by white blood cells.

The other three options are not blood cell types that play a key role in the immune response:

• Platelets are involved in blood clotting.
• Plasma is the liquid portion of the blood.
• Red blood cells carry oxygen to the tissues and carbon dioxide away from the tissues.

Answer: transferrin-bound iron into erythrocytes

The transferrin receptor is a protein found on the surface of cells, including erythrocytes (red blood cells). It plays a crucial role in facilitating the uptake of iron that is bound to transferrin, a transport protein in the plasma. The transferrin receptor binds to transferrin-bound iron and allows the iron to enter the erythrocytes where it can be used in the production of hemoglobin, the oxygen-carrying molecule in red blood cells. This process is essential for maintaining proper iron balance in the body.

Answer: Ferritin

Ferritin is a protein that stores iron within cells and releases it in a controlled manner when needed for various metabolic processes, including the production of hemoglobin and other iron-dependent proteins. Hemosiderin is another iron storage form found in cells but represents a less readily available and more insoluble form of stored iron. Transferrin is a transport protein that carries iron in the blood, and hemoglobin is the protein found in red blood cells that binds and transports oxygen.

Answer: MCHC

MCHC is a measure of the concentration of hemoglobin in a given volume of packed red blood cells. It is expressed as a percentage and helps assess how much hemoglobin is present in the RBCs, providing information about their saturation with hemoglobin. MCV (Mean Corpuscular Volume) measures the average volume of a single red blood cell, while MCH (Mean Corpuscular Hemoglobin) measures the average amount of hemoglobin in a single red blood cell.

Answer: Microtubules

Microtubules are a component of the cytoskeleton, a network of protein filaments and tubules within the cell that provides structural support and plays a role in cell shape, intracellular transport, and cell division. Microtubules are long, hollow tubes made of tubulin protein subunits and are involved in maintaining the overall shape and structure of the cell. They also serve as tracks for intracellular transport by motor proteins. While other structures, like spindle fibers and centrioles, play important roles in cell division, they are not primarily responsible for maintaining the shape of the cell. Ribosomes, on the other hand, are involved in protein synthesis and are not directly related to cell shape.

Answer: Polarizing

Polarizing microscopy is a technique that employs polarized light to examine substances that interact with polarized light, such as certain types of crystals. Crystals, when placed between two polarizers, can rotate the plane of polarization of light passing through them, and this property is called optical activity. Polarizing microscopy is useful for studying the optical properties and identifying the type of crystals based on their birefringence and optical activity. This makes it a valuable tool in crystallography and mineralogy, among other fields. The other microscopy techniques mentioned, such as compound brightfield, darkfield, and phase-contrast microscopy, are not specifically designed for the identification of crystals based on their optical properties.

Answer: Tense

Hemoglobin exhibits a phenomenon known as cooperativity, where the binding of oxygen to one subunit of the Hb molecule increases the affinity of the other subunits for oxygen. In the tense (T) state of the Hb molecule, which occurs when oxygen has not yet bound to any subunit, the affinity for oxygen is the lowest. As oxygen binds to one subunit, it shifts the Hb molecule to the relaxed (R) state, where the affinity for oxygen increases, making it easier for the remaining subunits to bind oxygen. Tense Hb is often found in tissues with lower oxygen levels, while relaxed Hb is prevalent in the lungs, where oxygen is abundant. Arterial and venous forms refer to the oxygen saturation of Hb in the arteries and veins, respectively, and are determined by the oxygen content in the blood at those locations.

Answer: 16

Erythrocytes (red blood cells) are produced through a process called erythropoiesis, which starts with multipotent hematopoietic stem cells in the bone marrow. These stem cells can differentiate and give rise to multiple progenitor cells, each of which can eventually develop into a red blood cell. The process typically involves several stages, and during each stage of differentiation, the number of cells produced increases. On average, one multipotential stem cell can give rise to around 16 erythrocytes as it goes through these stages of development.

Answer: Only Erythroblasts

During the mesoblastic phase of hematopoiesis, which occurs in the yolk sac, only primitive erythroid cells, also known as erythroblasts, are produced. These cells produce Gower 1, Gower 2, and Portland hemoglobins.

Hemoglobin F (HbF) and hemoglobin A2 (HbA2) are not produced until the hepatic phase of hematopoiesis, which occurs in the liver. Hemoglobin A (HbA) is the major hemoglobin produced in adults and is not produced until the medullary phase of hematopoiesis, which occurs in the bone marrow.

Therefore, the only type of cell that develops from the yolk sac (mesoblastic phase) is the erythroblast.

Answer: Alpha and Beta

Hemoglobin A is the primary hemoglobin found in adult human red blood cells, and it consists of two alpha chains and two beta chains. These chains come together to form the tetrameric structure of Hb A, enabling it to transport oxygen in the blood.

Answer: MCH

MCH is expressed in picograms (pg) and represents the average amount of hemoglobin within a single red blood cell. It is used to assess the quantity of hemoglobin in each RBC, while MCV (Mean Corpuscular Volume) measures the average volume of a single red blood cell, and MCHC (Mean Corpuscular Hemoglobin Concentration) assesses the concentration of hemoglobin in RBCs.

Answer: Ferrous

Heme is a complex molecule found in hemoglobin, myoglobin, and various other heme-containing proteins. The iron atom at the center of the heme molecule is typically in the ferrous (Fe²⁺) state, which is essential for its oxygen-binding and transport functions in hemoglobin and myoglobin. The iron can transition between the ferrous and ferric states, but it is primarily in the ferrous state in these proteins to facilitate oxygen binding and release. “Ferro” is not a standard term but may refer to ferrous iron, while “ferric” is the oxidized form of iron (Fe³⁺), which is less common in heme-containing proteins like hemoglobin. “Apoferritin” is a protein involved in iron storage but is not the form of iron within the heme molecule.

Answer: Pancytopenia

Pancytopenia is a condition characterized by a deficiency of all three major blood cell types in the peripheral blood, including red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia). It can occur in various medical conditions and is not limited to a single blood cell type.

Answer: Peripheral protein

The erythrocyte (red blood cell) membrane consists of a lipid bilayer embedded with proteins. The peripheral proteins are located on the inner and outer surfaces of the lipid bilayer. These peripheral proteins play a significant role in maintaining the cell’s shape, structure, and deformability, allowing red blood cells to squeeze through narrow capillaries and endure the mechanical stress of circulation. Integral proteins are embedded within the lipid bilayer, and they have other functions, such as transporting molecules across the membrane, but they are not primarily responsible for the cell’s shape and deformability.

Answer: IL-3

Interleukin-3 (IL-3) is a multilineage cytokine because it stimulates the growth and differentiation of multiple types of blood cells (both myeloid and lymphoid lineages) from hematopoietic stem cells in the bone marrow.

Other options:

• IL-4: Involved in B-cell activation and IgE class switching
• IL-1: Pro-inflammatory cytokine
• IL-2: Promotes T-cell proliferation

Answer: Thrombocytopenia

The medical term for a low platelet count in the blood is Thrombocytopenia. Thrombocytopenia is a condition characterized by a reduced number of platelets in the blood, which can lead to an increased risk of bleeding and difficulty with clot formation. It is an important factor in the body’s ability to maintain proper hemostasis. Leukopenia refers to a low white blood cell count, thrombocytosis is an elevated platelet count, and anemia is a condition characterized by a low red blood cell count or reduced hemoglobin levels.

Answer: Eosinophils

Eosinophils are a type of white blood cell that plays a key role in the immune response to allergens and parasitic infections. During allergic reactions, such as hay fever, asthma, or allergic skin conditions, the body often recruits and activates eosinophils to the affected tissues. Eosinophils release granules containing inflammatory substances that can contribute to the symptoms of allergies, such as itching, inflammation, and mucus production. Elevated eosinophil levels in the blood or at the site of allergic reactions are a common feature of allergy-related inflammation.

Answer: Surrounding macrophages near the sinus membrane

Hematopoiesis, the process of blood cell formation, primarily occurs in the bone marrow. Red blood cell precursors, known as erythroblasts, are found in close proximity to macrophages near the sinusoidal membrane of the bone marrow. Macrophages play a crucial role in the process by removing the nuclei from maturing erythroblasts and facilitating the release of mature red blood cells into the bloodstream. This interaction helps ensure the proper development and release of red blood cells.

Answer: inhibits DNA synthesis by acting as a ribonucleotide reductase inhibitor

Hydroxyurea is a medication commonly used to treat conditions like sickle cell anemia and certain types of cancer. It acts by inhibiting the enzyme ribonucleotide reductase, which is responsible for the synthesis of deoxyribonucleotides, the building blocks of DNA. By inhibiting this enzyme, hydroxyurea reduces the production of DNA and can help slow down the growth of cells, particularly in rapidly dividing cells like cancer cells. The other options are not accurate descriptions of the primary mechanism of hydroxyurea.

Answer: End of 5th month

The bone marrow becomes the primary site of hematopoiesis during the end of the 5th month of fetal development. Prior to this, hematopoiesis primarily occurs in other locations such as the yolk sac and liver. By the end of the 5th month, the bone marrow takes over as the primary site for blood cell production, a role it continues throughout a person’s life.

Answer: NADPH and reduced glutathione

The HMP pathway is important in red blood cells for generating reducing equivalents in the form of NADPH (nicotinamide adenine dinucleotide phosphate), which is used to protect the cell from oxidative stress and to maintain the hemoglobin molecule in its reduced (ferrous) state. Reduced glutathione is also crucial for protecting the cell from oxidative damage. While the pathway does produce some pentoses (sugar molecules), its primary role in red blood cells is the generation of NADPH and the maintenance of redox balance, rather than the production of energy (ATP) or other purine metabolites.

Answer: Inflammation

ESR is a blood test that measures the rate at which red blood cells settle in a tube over a specific period of time. It is a non-specific marker of inflammation. When inflammation occurs in the body, certain proteins, including fibrinogen and globulins, increase in the blood, causing red blood cells to clump together and settle more rapidly. As a result, an elevated ESR is often associated with various inflammatory conditions, such as infections, autoimmune diseases, and tissue damage. The other options, osteoarthritis, polycythemia, and decreased globulins, are not typically associated with elevated ESR values.

Answer: To replace lost lipids in the membrane

The RBC membrane is constantly losing lipids due to a variety of factors, such as oxidative damage and enzymatic degradation. Lipid exchange helps to maintain the integrity of the membrane by replacing lost lipids with new ones from the plasma.

The other options listed are not primary functions of lipid exchange between the RBC membrane and the plasma.

• While lipid exchange can play a role in the excretion of lipid-soluble RBC waste products, this is not a primary function.
• The composition of the interior and exterior lipid layers of the RBC membrane is not symmetrical. Lipid exchange does not play a role in ensuring symmetry between the two layers.
• Lipid-soluble nutrients are not provided to the RBC via lipid exchange. Lipid-soluble nutrients are transported into the RBC via specific transporters.

Answer: Proper Handwashing

Proper handwashing is a fundamental and highly effective practice in preventing the spread of disease. It helps remove dirt, bacteria, and viruses from hands, reducing the risk of transmission to oneself and others. While other practices like wearing masks, disposable lab coats, or labeling specimens are important in specific healthcare settings, proper handwashing is universally essential in preventing the spread of diseases in various situations, including patient care, food handling, and everyday activities. It’s a primary measure to maintain good hygiene and reduce the risk of infections.

Answer: Iliac Crest (hip)

The iliac crest, which is part of the pelvic bone, is a common site for bone marrow aspiration and biopsy procedures. It is often preferred because it provides relatively easy access to a significant amount of active bone marrow. The femur (thigh) and tibia (shin) are also used in certain cases, but the iliac crest is generally the primary choice for bone marrow harvesting due to its accessibility and the quantity of bone marrow it can yield. The distal radius (forearm) is not commonly used for bone marrow harvesting.

Answer: PPI, H2 blockers

Proton Pump Inhibitors (PPIs) and H2 blockers are commonly used medications to reduce stomach acid production. Prolonged use of these drugs can affect the absorption of vitamin B12 and iron from the digestive tract, potentially leading to deficiencies over time. Therefore, there is a drug interaction between these medications and both vitamin B12 and iron. Methyldopa and Metformin do not have the same known interactions with vitamin B12 and iron.

Answer: Stage 0

In the Rai Staging System for Chronic Lymphocytic Leukemia (CLL), absolute lymphocytosis without other signs or symptoms, such as lymphadenopathy, hepatosplenomegaly, anemia, or thrombocytopenia, is categorized as Stage 0.

The Rai Staging System has the following stages:

• Stage 0: Lymphocytosis (high lymphocyte count) without other signs or symptoms.
• Stage I: Lymphocytosis with lymphadenopathy (enlarged lymph nodes).
• Stage II: Lymphocytosis with hepatosplenomegaly (enlarged liver and spleen).
• Stage III: Lymphocytosis with anemia.
• Stage IV: Lymphocytosis with thrombocytopenia (low platelet count).

Stage 0 represents an early stage of CLL with a relatively better prognosis, as it indicates the presence of the disease without significant complications or symptoms.

Answer: 4.6-6.0

This range may vary slightly depending on the laboratory and reference values used, but the most commonly accepted range falls within 4.6-6.0 million RBCs per mcL for adult men.

Answer: Glycoprotein

Glycoproteins are proteins that have carbohydrates (sugar molecules) attached to them. These molecules play essential roles in cell adhesion, signaling, and various cellular processes. They are a crucial component of the cell membrane, which separates the cell from its external environment and is involved in cell recognition and interaction with other cells and molecules. Lipoproteins are a different class of molecules that contain lipids and proteins, mucoproteins are proteins with mucous carbohydrates, and nucleoproteins are proteins associated with nucleic acids. Glycoproteins are the most prevalent type of protein in cell membranes due to their significance in cell communication and recognition.

Answer: Loss of nucleus

RBCs are unique among cells in the human body because they lack a nucleus and other organelles. This loss of the nucleus during their maturation in the bone marrow limits their ability to repair and renew themselves. As a result, RBCs have a finite lifespan and are eventually removed from circulation by the spleen and liver once they become too old or damaged. The absence of a nucleus also contributes to their biconcave shape and increased flexibility, which is important for their role in transporting oxygen through narrow capillaries.

Answer: In two layers that are not symmetric in composition

The lipid bilayer of the RBC membrane is asymmetric, meaning that the composition of lipids in the inner and outer leaflets of the bilayer is different. This asymmetry is essential for maintaining the integrity and functions of the cell membrane, such as its flexibility and deformability. The hydrophilic portions of the lipids face the aqueous environment both inside and outside the cell, while the hydrophobic portions are located within the interior of the lipid bilayer. This arrangement allows the cell membrane to function as a selectively permeable barrier and contributes to its structure and properties.

Answer: 120 days

The average lifespan of a red blood cell (RBC) is approximately 120 days. After this period, RBCs are removed from circulation, primarily in the spleen and liver, and are replaced by new RBCs produced in the bone marrow. The lifespan of RBCs can vary slightly among individuals and under different conditions, but approximately 120 days is a common reference value.

Answer: No Neurological Symptoms in Folic Acid

Both vitamin B12 and folic acid deficiencies can lead to a type of anemia, and they share some common symptoms such as fatigue and pallor. However, one key distinguishing factor is that vitamin B12 deficiency can lead to neurological symptoms, including tingling, numbness, and problems with coordination. These neurological symptoms are not typically seen in folic acid deficiency. This difference is important in clinical diagnosis and treatment. Glossitis, muscle wasting, and dizziness can be symptoms of both deficiencies and are not specific enough to differentiate between them.

Answer: 4.0-5.0

This range may vary slightly depending on the laboratory and reference values used, but the most commonly accepted range falls within 4.0-5.0 million RBCs per mcL for adult women. None of the provided options exactly matches this range, but 4.2-5.2 is the closest approximation.

Answer: 2.5

To calculate the total WBC count, we can use the following formula:

WBC count = (Number of cells counted / Number of squares counted) * Dilution factor * Volume factor

In this case, the number of cells counted is 100, the number of squares counted is 8 (four corner squares on both sides of the hemacytometer), the dilution factor is 20, and the volume factor is 1 (since the volume of the hemocytometer chamber is 1 mm³).

Plugging in these values, we get:

WBC count = (100 / 8) * 20 * 1 = 250

To convert this to x10⁹/L, we multiply by 10⁹/L:

WBC count = 250 * 10⁹/L = 2.5 x 10⁹/L

Therefore, the total WBC count is 2.5 x 10⁹/L.

Answer: Coombs test

The Coombs test, also known as the Direct Antiglobulin Test (DAT) or Indirect Antiglobulin Test (IAT), is a diagnostic test used to detect hemolytic anemia. Hemolytic anemia is a condition in which red blood cells are destroyed more quickly than they can be produced, often due to an autoimmune reaction or other factors. The Coombs test helps identify the presence of antibodies or complement proteins on the surface of red blood cells, which can lead to their premature destruction. This test is a crucial tool in diagnosing and understanding the underlying causes of hemolytic anemia, whereas the other options (genetic testing, peripheral blood smear, Schilling test) are not typically used for this purpose.

Answer: All Options

Thromboembolism is a general term for a condition where a blood clot (thrombus) forms in a blood vessel and then dislodges, traveling through the bloodstream until it becomes lodged in a smaller vessel, causing a blockage. Deep Vein Thrombosis (DVT) is the formation of a blood clot in a deep vein, typically in the leg, and Pulmonary Embolism (PE) occurs when a clot from a DVT or another source travels to the lungs, causing a blockage. All of these conditions can be fatal and are related to clot/thrombus formation in the blood circulation.

Answer: All Options

Hypocupremia refers to a deficiency of copper in the body. It can be associated with various medical conditions, including osteoporosis, nephrotic disease (kidney-related disorder), sprue, celiac disease (intestinal disorders), cardiovascular disease, and colon cancer. Copper is an essential trace element in the body, and its deficiency can have a wide range of health implications. Therefore, it can be seen in all the conditions listed in the options.

Answer: Hypochromic Anemia

Hypochromic anemia refers to a type of anemia where the red blood cells are paler than normal because they have a reduced amount of hemoglobin. In some cases, this condition can be inherited, and it is often associated with disorders like thalassemia or certain genetic hemoglobinopathies (e.g., Hb E/β-thalassemia, Hb H disease). In these inherited conditions, there can be defects in the synthesis or structure of hemoglobin, leading to the inability to use iron properly in the hemoglobin synthesis process.

Answer: Dipyridamole

Dipyridamole is an antiplatelet medication that works by inhibiting platelet aggregation and increasing the level of cyclic AMP, leading to vasodilation and decreased platelet adhesion. This mechanism helps prevent blood clots and can be used in various cardiovascular conditions. Sulfinpyrazone and ticlopidine are also antiplatelet medications but have different mechanisms of action.