Hematology MCQs with Answer and Explanations | Chapter 9

Answer: Removal of imperfect and aging cells

The spleen acts as a filter for your blood, removing old, damaged, or misshapen red blood cells. It does this by identifying and breaking down these cells with specialized white blood cells called macrophages.

The other options are incorrect:

• Storage of red blood cells: While the spleen can store a small reserve of red blood cells, its primary function isn’t storage. The bone marrow is the main site for red blood cell production and storage.
• Production of red blood cells: Red blood cells are primarily produced in the bone marrow. The spleen doesn’t play a significant role in their creation.
• Synthesis of erythropoietin: Erythropoietin is a hormone produced by the kidneys that stimulates red blood cell production in the bone marrow. The spleen isn’t involved in erythropoietin synthesis.

Answer: Iron, protoporphyrin, and globin

When red blood cells are removed from circulation, hemoglobin is broken down into iron, protoporphyrin (which is further broken down into biliverdin and then bilirubin), and globin (which is broken down into amino acids).

The other options are incorrect:

• Iron, porphyrin, and amino acids: Hemoglobin breakdown does not result directly in porphyrin but in protoporphyrin, which is a specific type of porphyrin.
• Heme, protoporphyrin, and amino acids: Heme is a component of hemoglobin that is broken down into iron and protoporphyrin. The breakdown process does not result in heme as a final product.
• Heme, hemosiderin, and globin: Hemosiderin is an iron-storage complex that forms when there is excess iron in the body, but it is not a direct product of hemoglobin breakdown.

Answer: Denatureed hemoglobin inclusiond that are readily removed by the spleen

Heinz bodies are clumps of denatured (damaged) hemoglobin protein within red blood cells. The spleen, acting as a filter, identifies and removes these damaged cells containing Heinz bodies.

The other options are incorrect:

• Readily identified with polychrome stains: Regular blood stains like Wright-Giemsa stain wouldn’t show Heinz bodies. They require special supravital stains like brilliant green for visualization.
• Rarely found in glucose-6-phosphate dehydrogenase deficient erythrocytes: In fact, Heinz bodies are quite common in red blood cells with glucose-6-phosphate dehydrogenase (G6PD) deficiency because this enzyme deficiency makes them more susceptible to damage.
• Closely associated with spherocytes: While Heinz bodies can sometimes be present in spherocytes (abnormally round red blood cells), the association isn’t always direct. Heinz bodies can occur in other red blood cell shapes as well.

Answer: Erythrocytes

Erythrocytes, also known as red blood cells, are specialized cells responsible for transporting oxygen throughout the body. They contain hemoglobin, a protein that binds oxygen molecules efficiently.

The other options are incorrect:

• Granulocytes: These are a type of white blood cell involved in the immune response and fighting infections. They don’t carry oxygen or carbon dioxide.
• Lymphocytes: Similar to granulocytes, lymphocytes are another type of white blood cell crucial for the immune system. They also aren’t involved in gas transport.
• Thrombocytes: These are also known as platelets and play a vital role in blood clotting to prevent bleeding. They don’t have a role in gas transport.

Answer: Stimulate RNA synthesis of erythroid cells

Erythropoietin primarily stimulates the production and maturation of red blood cells by promoting RNA synthesis in erythroid precursor cells in the bone marrow.

The other options are incorrect:

• Shorten the replication time of the granulocytes: Erythropoietin specifically targets erythroid cells (red blood cell precursors), not granulocytes (a type of white blood cell).
• Increase colony-stimulating factors produced by the B-lymphocytes: Erythropoietin does not affect B-lymphocytes or the production of colony-stimulating factors; it is specific to red blood cell production
• Decrease the release of marrow reticulocytes: Reticulocytes are immature red blood cells released from the bone marrow. EPO actually works in the opposite way, stimulating their production and release into circulation.

Answer: Spherocytes

Spherocytes, which are sphere-shaped red blood cells, are most commonly associated with an increased mean corpuscular hemoglobin concentration (MCHC) due to their reduced cell membrane relative to cell volume.

The other options are incorrect:

Tear drop cells: These elongated red blood cells, also known as dacrocytes, are not typically associated with increased MCHC. Target cells: These red blood cells have a central pale area with a darker peripheral ring. They are not directly linked to changes in MCHC. Sickle cells: While sickle cell disease can cause alterations in red blood cell shape, it doesn’t necessarily lead to a consistent increase in MCHC. The abnormal shape of sickle cells can affect MCHC measurements in complex ways.

Answer: Red cell membrane defects

Hereditary spherocytosis, hereditary elliptocytosis, hereditary stomatocytosis, and paroxysmal nocturnal hemoglobinuria all involve defects in the red cell membrane, leading to various forms of hemolytic anemia.

The other options are incorrect:

• Autosomal dominant inheritance: While hereditary spherocytosis and hereditary elliptocytosis are often inherited in an autosomal dominant manner, paroxysmal nocturnal hemoglobinuria is an acquired condition and not inherited.
• Positive direct antiglobulin test: This test is typically positive in autoimmune hemolytic anemia, but it is not characteristic of these conditions, which involve intrinsic red cell defects.
• Measured platelet count: Platelet counts can be affected in paroxysmal nocturnal hemoglobinuria due to bone marrow involvement, but this is not a common characteristic of all the listed conditions.

Answer: Transferrin

Total iron-binding capacity (TIBC) measures the serum iron transporting capacity of transferrin, the main protein that binds and transports iron in the blood.

The other options are incorrect:

• Hemoglobin: Hemoglobin is the oxygen-carrying protein in red blood cells and does not transport iron in the blood.
• Ceruloplasmin: Ceruloplasmin is a copper-carrying protein in the blood and plays a role in iron metabolism but does not transport iron.
• Ferritin: Ferritin is an intracellular protein that stores iron and releases it in a controlled manner, not a transporter of iron in the bloodstream.

Answer: Iron Deficiency anemia

In iron deficiency anemia, erythrocyte protoporphyrin levels increase because iron is necessary for heme synthesis. When iron levels are low, protoporphyrin accumulates because it cannot be incorporated into heme.

The other options are incorrect:

• Acute intermittent porphyria: This condition is characterized by a deficiency of the enzyme porphobilinogen deaminase, leading to the accumulation of porphyrins, but it does not typically result in increased erythrocyte protoporphyrin levels.
• Porphyria cutanea tarda: This type of porphyria is characterized by the deficiency of the enzyme uroporphyrinogen decarboxylase, resulting in the accumulation of uroporphyrinogen and its precursors, but it does not typically result in increased erythrocyte protoporphyrin levels.
• Acute porphyric attack: During acute attacks of porphyria, various porphyrin precursors may accumulate, but this condition is not specifically associated with increased erythrocyte protoporphyrin levels.

Answer: Hematocrit

The different water content of erythrocytes and plasma affects the concentration of glucose in whole blood, making it a function of the hematocrit, which represents the volume percentage of red blood cells in whole blood.

The other options are incorrect:

• Leukocyte count: Glucose concentration in whole blood is not directly influenced by the leukocyte count, which represents the number of white blood cells.
• Erythrocyte count: While the number of erythrocytes may affect the overall volume of red blood cells in whole blood, it is the hematocrit (which considers both the volume and the packing arrangement of red blood cells) that directly influences glucose concentration.
• Erythrocyte indices: Erythrocyte indices such as mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) provide information about the size and hemoglobin content of red blood cells but do not directly influence glucose concentration in whole blood.

Answer: A1C

Hemoglobin A1C, also known as glycated hemoglobin, has glucose-6-phosphate attached to the amino-terminal valine of the beta chain. This occurs through a non-enzymatic reaction between hemoglobin and glucose in the bloodstream over time.

The other options are incorrect:

• S: Hemoglobin S is the abnormal hemoglobin found in sickle cell disease, and it does not have glucose-6-phosphate attached to the amino-terminal valine of the beta chain.
• C: Hemoglobin C is another abnormal hemoglobin variant, but it also does not have glucose-6-phosphate attached to the amino-terminal valine of the beta chain.
• A2: Hemoglobin A2 is a minor component of adult hemoglobin, but it does not have glucose-6-phosphate attached to the amino-terminal valine of the beta chain.

Answer: Exogenous triglycerides

Very low density lipoproteins (VLDL) transport endogenous triglycerides.

The other options are incorrect:

• Cholesterol from peripheral cells to the liver: This function is associated with high density lipoproteins (HDL), not VLDL.
• Cholesterol and phospholipids to peripheral cells: This function is associated with low density lipoproteins (LDL), not VLDL.
• Exogenous triglycerides: Exogenous triglycerides are transported by chylomicrons, not VLDL.

Answer:

Tetany, characterized by muscle cramps and tingling, can be a sign of hypocalcemia (low blood calcium). Calcium is crucial for nerve and muscle function, and low levels can lead to neuromuscular irritability.

The other options are incorrect:

• Phosphorus: While abnormal phosphorus levels can sometimes be associated with muscle weakness, it’s not the most immediate test for tetany.
• BUN (Blood Urea Nitrogen): This test is primarily used to assess kidney function and wouldn’t be the first choice for tetany.
• Glucose: Low blood sugar (hypoglycemia) can cause some neurological symptoms, but tetany is not a typical presentation.

Answer: Anisocytosis

Anisocytosis refers to a variation in the size of red blood cells. Normal red blood cells have a relatively uniform size, and significant size differences indicate anisocytosis.

The other options are incorrect:

• Hypochromia: This describes red blood cells that appear pale due to a hemoglobin deficiency.
• Poikilocytosis: This refers to red blood cells with abnormal shapes, not just size variations.
• Pleocytosis: This is an elevated white blood cell count, not a term related to red blood cell size.

Answer:

The iliac crest of the posterior hip bone is the preferred site for bone marrow aspiration and biopsy in adults. It’s a safe and relatively flat bone with easy access and minimal risk of complications.

The other options are incorrect:

• Sternum: While possible in some cases, the sternum is a thicker bone and carries a higher risk of complications like bleeding or pneumothorax (collapsed lung).
• Tibia: The tibia (shin bone) is not a common site for bone marrow procedures in adults due to its deeper location and risk of nerve or blood vessel injury.
• Spinous processes of the vertebra: The vertebrae in the spine are not typically used for bone marrow aspiration and biopsy because they are close to vital structures and technically more challenging to access safely.

Answer: ( Hct/RBC)x10

Mean cell volume (MCV) is calculated by dividing the hematocrit (Hct) by the red blood cell count (RBC) and multiplying by 10.

The other options are incorrect:

• (Hgb/RBC)x10: This equation calculates the mean corpuscular hemoglobin (MCH), not the mean cell volume (MCV).
• (Hct/Hgb)x100: This equation does not directly calculate MCV but is a variation that could be used to estimate the mean corpuscular hemoglobin concentration (MCHC).
• (Hgb/RBC)x100: This equation does not directly calculate MCV but is a variation that could be used to estimate the mean corpuscular hemoglobin concentration (MCHC).

Answer: Poikilocytosis

Poikilocytosis describes the presence of red blood cells with abnormal shapes on a blood smear. Wright’s stain is a common stain used to visualize blood cells, allowing identification of irregularly shaped erythrocytes.

The other options are incorrect:

• Anisocytosis: This refers to a variation in the size of red blood cells, not their shape.
• Hypochromia: This term describes red blood cells that appear pale due to a hemoglobin deficiency, not a shape abnormality.
• Polychromasia: This refers to the presence of slightly bluish red blood cells, indicating they are immature reticulocytes, not necessarily abnormally shaped.

Answer: 33.3% (.333)

Mean cell hemoglobin concentration (MCHC) is calculated by dividing the hemoglobin concentration (Hgb) by the hematocrit (Hct) and multiplying by 100.

List of Incorrect Options:

• 9.5% (.095): This value is incorrect because it does not involve the correct calculation for MCHC.
• 10.4% (.104): This value is incorrect because it does not involve the correct calculation for MCHC.
• 31.9% (.319): This value is incorrect because it does not involve the correct calculation for MCHC.

Answer: Siderocyte

An erythrocyte containing iron granules stained with Prussian blue is called a siderocyte.

The other options are incorrect:

• Spherocyte: These are red blood cells with a round, sphere-like shape. They don’t necessarily contain iron granules.
• Leptocyte: These are red blood cells with a thin, elongated shape. Iron granule presence isn’t their defining characteristic.
• Schistocyte: These are red blood cells with fragmented or irregularly shaped membranes. Similar to the other options, iron granules aren’t a defining feature.

Answer: 3.36 x 10^12/L

To find the RBC count per liter, multiply the number of cells counted by the dilution factor and by the conversion factor for the volume of the square.

The other options are incorrect:

• 1.68 x 10^12/L: This value is incorrect because it does not involve the correct calculation for the RBC count.
• 4.47 x 10^12/L: This value is incorrect because it does not involve the correct calculation for the RBC count.
• 6.66 x 10^12/L: This value is incorrect because it does not involve the correct calculation for the RBC count.

Answer: Neutrophils

Neutrophils are a type of phagocytic white blood cell that plays a crucial role in the body’s immune defense. They engulf and destroy bacteria using various mechanisms, including the production of lysozymes. Lysozymes are enzymes that break down the cell walls of bacteria, contributing to their elimination.

The other options are incorrect:

• Eosinophils: These are another type of white blood cell involved in allergic reactions and parasite defense. While they have some digestive enzymes, they are not the primary producers of lysozymes with strong antibacterial activity.
• Lymphocytes: These are immune cells responsible for the adaptive immune response. They don’t typically directly engulf and destroy bacteria like neutrophils.
• Platelets: Platelets are involved in blood clotting and don’t have phagocytic or lysozyme-producing capabilities.

Answer: 3.1%

To correct the reticulocyte count for the degree of anemia, multiply the reticulocyte count by the ratio of the patient’s hematocrit to the normal hematocrit.

The other options are incorrect:

• 1.40%: This value is incorrect because it does not involve the correct calculation for the corrected reticulocyte count.
• 3.50%: This value is incorrect because it does not involve the correct calculation for the corrected reticulocyte count.
• 14%: This value is incorrect because it does not involve the correct calculation for the corrected reticulocyte count.

Answer: Sickle cell anemia

Sickle cell anemia would be associated with decreased osmotic fragility.

The other options are incorrect:

• Hereditary spherocytosis: Hereditary spherocytosis is associated with increased osmotic fragility due to the abnormal shape and increased susceptibility of red blood cells to hemolysis.
• Hemolytic disease of the newborn: Hemolytic disease of the newborn is associated with increased osmotic fragility due to the destruction of fetal red blood cells by maternal antibodies.
• Acquired hemolytic anemia: Acquired hemolytic anemias may or may not affect osmotic fragility, depending on the underlying cause. It is not specifically associated with decreased osmotic fragility.

Answer: Red cells would be stained too pink

Wright’s stain is a pH-dependent stain. The optimal pH for staining red blood cells (erythrocytes) a pinkish-orange color is around 6.8.

The other options are incorrect:

1. White cell cytoplasm would be stained too blue: The pH of the buffer does not affect the staining of white cell cytoplasm.
2. Red cells would be stained too blue: A buffer at pH 6.0 would not cause red cells to be stained too blue on a Wright’s-stained smear.
3. Red cells would lyse on the slide: The pH of the buffer does not directly cause red cells to lyse on the slide.

Answer: Heinz bodies

These are denatured hemoglobin precipitates within red blood cells. They are best visualized with supravital stains like new methylene blue, which highlight unstable hemoglobin. Wright’s stain might not stain Heinz bodies clearly or might miss them altogether.

The other options are incorrect:

• Basophilic stippling: This refers to the aggregation of ribosomal RNA within red blood cells. These can be visualized on a Wright’s stained smear as a fine to coarse, basophilic (blue) stippling pattern in the cytoplasm.
• Howell-Jolly bodies: These are small, round nuclear fragments that can be left behind in mature red blood cells. They appear as basophilic inclusions on a Wright’s-stained smear.
• Siderotic granules: These are iron-containing granules within red blood cells. While supravital stains can sometimes be used to detect iron stores, Wright’s stain can also reveal these granules as a faint blue or greenish hue.

Answer: MCH

Mean corpuscular hemoglobin (MCH) is the amount of hemoglobin per red blood cell and is not directly influenced by changes in hematocrit (Hct).

The other options are incorrect:

• MCV: Mean corpuscular volume (MCV) is the average volume of red blood cells and is influenced by changes in Hct.
• MCHC: Mean corpuscular hemoglobin concentration (MCHC) is the concentration of hemoglobin in red blood cells and is influenced by changes in Hct.
• Red cell distribution width (RDW): RDW is a measure of the variation in size of red blood cells and is not directly influenced by changes in Hct.

Answer: Reticulocytes

Reticulocytes are immature red blood cells that still contain some RNA material. These can be stained with special techniques to differentiate them from mature red blood cells. The Miller disk helps ensure consistent counting within a defined area of the smear.

The other options are incorrect:

• Platelets: Platelets are much smaller than red blood cells and are not routinely counted using a Miller disk.
• Sickle cells: Sickle-shaped red blood cells can be identified on a Wright’s-stained peripheral blood smear without the need for a Miller disk.
• Nucleated red blood cells: While rare in healthy adults, nucleated red blood cells can also be identified on a peripheral blood smear without a Miller disk.

Answer: Blood drawn in a sodium citrate tube

Erythrocyte sedimentation rate (ESR) is not influenced by the type of anticoagulant used for blood collection, so drawing blood in a sodium citrate tube would not affect ESR.

The other options are incorrect:

• Anisocytosis, Poikilocytosis: As mentioned earlier, variations in red blood cell size and shape can influence ESR.
• Plasma proteins: Increased levels of specific plasma proteins can accelerate sedimentation and raise the ESR.
• Caliber of the tube: The diameter of the blood collection tube can slightly influence the ESR due to variations in settling distance.

Answer: Supravital staining

Supravital staining is the staining method used most frequently to stain and count reticulocytes, as it allows for the visualization of residual RNA in reticulocytes.

The other options are incorrect:

• Immunofluorescence: Immunofluorescence is a technique used to detect specific proteins using fluorescently labeled antibodies and is not commonly used for staining and counting reticulocytes.
• Romanowsky staining: Romanowsky staining, such as Wright’s or Giemsa stain, is commonly used for staining blood smears to visualize cell morphology but is not specific for reticulocytes.
• Cytochemical staining: Cytochemical staining involves staining cells to detect specific cellular components or functions and is not typically used for reticulocyte staining and counting.

Answer: Conductivity varies proportionally to the number of cells

The Coulter principle for counting cells is based on the fact that conductivity varies proportionally to the number of cells suspended in an electrolyte solution.

The other options are incorrect:

• Isotonic solutions conduct electricity better than cells do: This statement is incorrect. Isotonic solutions have a similar conductivity to cells.
• Cells conduct electricity better than saline does: While cells can conduct electricity, this statement is incorrect in the context of the Coulter principle, which relies on the variation in conductivity caused by cells.
• Isotonic solutions cannot conduct electricity: Isotonic solutions, such as saline, can conduct electricity, although the conductivity is different from that of cells.

Answer: Nucleated RBC’s are counted as leukocytes

Nucleated red blood cells (RBCs) are often mistaken for leukocytes during manual white blood cell (WBC) counting, leading to a falsely elevated WBC count. A correction is necessary to exclude nucleated RBCs from the WBC count.

The other options are incorrect:

• The WBC count would be falsely lower: This statement is incorrect. Nucleated RBCs are counted as leukocytes, leading to a falsely elevated WBC count, not a lower one.
• The RBC count is too low: Nucleated RBCs do not affect the RBC count; they affect the WBC count.
• Nucleated RBCs are confused with giant platelets: Nucleated RBCs are not typically confused with giant platelets. They are often mistaken for leukocytes during WBC counting.

Answer: Anisocytosis

An increased red cell distribution width (RDW) on a Coulter counter analyzer correlates with anisocytosis, indicating variability in red blood cell size.

List of Incorrect Options:

• Spherocytosis: Spherocytosis is characterized by the presence of spherocytes, which are uniformly sized, not varying in size. Therefore, it is not typically associated with an increased RDW.
• Leukocytosis: Leukocytosis refers to an elevated white blood cell count and is not directly related to red blood cell size variability measured by RDW.
• Presence of NRBCs: Nucleated red blood cells (NRBCs) are immature red blood cells and are not directly related to red blood cell size variability measured by RDW.

Answer: MCV 80 um^3 MCH 36.5 pg MCHC 39%

Spherocytosis is characterized by.

• Microcytosis (↓ MCV): Sphered red blood cells have a reduced volume, leading to a lower MCV compared to the normal range (typically 80-100 um^3).
• Normal or slightly increased MCH: The total amount of hemoglobin within a red blood cell might be normal or slightly elevated despite the smaller size.
• Increased MCHC (↑ MCHC): Due to the loss of cell membrane surface area in spherocytes, the hemoglobin concentration within the remaining cell volume becomes more concentrated, resulting in an increased MCHC value (typically above 36%).

The other options are incorrect:

• Set 1 (MCV 76, MCH 19.9, MCHC 28): Both MCV and MCHC are outside the normal range, suggesting microcytosis (small cells) with low hemoglobin content, not spherocytosis.
• Set 2 (MCV 90, MCH 30.5, MCHC 32.5): MCV is slightly high, and MCHC is within the normal range. This doesn’t suggest spherocytosis.
• Set 4 (MCV 81, MCH 29, MCHC 34): MCV is close to normal, MCH is slightly low, and MCHC is elevated but not as high as Set 3. While there might be microcytosis (low MCH), the MCHC isn’t high enough to be strongly suggestive of spherocytosis.

Answer: Deoxyhemoglobin

Hemoglobin is the iron-containing protein in red blood cells responsible for transporting oxygen throughout the body. Deoxyhemoglobin is the form of hemoglobin that carries oxygen from the lungs to tissues. It binds oxygen molecules reversibly at specific sites on the hemoglobin molecule.

The other options are incorrect:

• Carboxyhemoglobin: Carboxyhemoglobin is formed when carbon monoxide binds to hemoglobin, and high levels can be toxic.
• Methemoglobin: Methemoglobin is an oxidized form of hemoglobin in which the iron is in the ferric state (Fe3+) rather than the ferrous state (Fe2+), leading to decreased oxygen-carrying capacity.
• Sulfhemoglobin: This form of hemoglobin arises when hemoglobin reacts with certain medications or chemicals. It also cannot bind oxygen and can contribute to anemia.

Answer: Lymphocyte

In aplastic anemia, there is a reduction in all types of blood cells, including leukocytes. Lymphocytes are often the major type of leukocyte observed in the peripheral smear due to their longer lifespan compared to other types of leukocytes.

The other options are incorrect:

• Segmented neutrophil: While neutropenia may occur in aplastic anemia, it is not the major type of leukocyte seen in the peripheral smear.
• Monocyte: Monocytes may be present in the peripheral smear, but they are not typically the major type of leukocyte observed in aplastic anemia.
• Eosinophil: Eosinophils may be present in the peripheral smear, but they are not typically the major type of leukocyte observed in aplastic anemia.

Answer: 20-50%

Lymphocytes are a major type of white blood cell that play a crucial role in the adaptive immune system. The normal percentage of lymphocytes in the white blood cell differential count (WBC differential) for adults falls within the range of.

The other options are incorrect:

• 10-20%: This range is too low for normal lymphocyte levels in adults.
• 5-10%: This is significantly lower than the expected range and suggests a potential lymphopenia (low lymphocyte count).
• 50-70%: While an elevated lymphocyte count (lymphocytosis) can occur in some conditions,pen_spark 50-70% is higher than the upper limit of the normal range in adults.

Answer: 6 months – 2 years

In infants and toddlers aged 6 months to 2 years, a higher percentage of lymphocytes in the total white blood cell count is considered normal due to the immature immune system.

The other options are incorrect:

• 40-60 years: In adults aged 40-60 years, a lymphocyte percentage as high as 60% would be considered abnormally high.
• 11-15 years: In adolescents aged 11-15 years, a lymphocyte percentage as high as 60% would be considered abnormally high.
• 4-6 years: In children aged 4-6 years, a lymphocyte percentage as high as 60% would be considered abnormally high.

Answer: Bands 6%

A significant increase in bands (immature neutrophils) above the normal range (usually < 3-5%) suggests the presence of an underlying infection or inflammatory process, warranting a manual review of the peripheral smear for confirmation and further evaluation.

The other options are incorrect:

• Segs 70%: The percentage of segmented neutrophils (segs) within the normal range does not typically warrant manual review.
• Mono 15%: The percentage of monocytes within the normal range does not typically warrant manual review.
• Eos 2%: The percentage of eosinophils within the normal range does not typically warrant manual review.

Answer: Basophilic normoblast

Hemoglobin formation begins during the basophilic normoblast stage of erythrocytic maturation, which is characterized by the initiation of hemoglobin synthesis.

The other options are incorrect:

• Reticulocyte: Reticulocytes are immature red blood cells that have already completed hemoglobin synthesis and have extruded their nuclei.
• Pronormoblast: Pronormoblasts are the earliest stage of erythrocytic maturation and are not yet actively synthesizing hemoglobin.
• Polychromatic normoblast: Polychromatic normoblasts are further along in maturation than basophilic normoblasts and have already initiated hemoglobin synthesis.

Answer: All of the above

The hemoglobin-oxygen dissociation curve depicts the relationship between the partial pressure of oxygen (pO2) and the percentage of hemoglobin saturated with oxygen (HbO2). A shift to the right on this curve indicates a decreased affinity of hemoglobin for oxygen, making it easier for oxygen to unload at the tissues.

• Increases in 2,3-diphosphoglycerate (2,3 DPG): 2,3 DPG binds to hemoglobin at a specific site, reducing its affinity for oxygen and promoting oxygen release at the tissues.
• Acidosis: Lower pH levels (acidosis) favor the dissociation of oxygen from hemoglobin.
• Hypoxia: Low oxygen tension (hypoxia) also decreases hemoglobin’s affinity for oxygen, facilitating oxygen release in hypoxic tissues.

Answer: B4

Hemoglobin H (Hgb H) is formed by the aggregation of β-globin chains. Therefore, the characteristic configuration of Hgb H is B4, indicating four β-globin chains.

The other options are incorrect:

• Y^4: This notation typically represents tetramers of γ-globin chains, which are not characteristic of Hgb H.
• A2-y2: This notation represents tetramers composed of two α-globin chains and two γ-globin chains, which are not characteristic of Hgb H.
• A2-b2: This notation represents tetramers composed of two α-globin chains and two β-globin chains, which is the typical structure of adult hemoglobin (HbA), not Hgb H.

Answer: All of the above

Autoagglutination of red blood cells (RBCs) at room temperature occurs when red blood cells clump together due to antibodies or other factors binding to their surfaces. This clumping can cause several issues when analyzing a blood sample:

• Low RBC count: When red blood cells are agglutinated, they are more likely to be stuck together or adhere to the walls of the collection tube. This can lead to an underestimation of the actual number of red blood cells in the blood sample, resulting in a falsely low RBC count.
• High MCV (Mean Corpuscular Volume): Automated cell counters measure the size of individual cells as they pass through an aperture. When red blood cells are agglutinated, they may appear larger than they actually are due to the clumping of multiple cells. This can lead to an erroneously high MCV value.
• Low hematocrit: Hematocrit is the percentage of blood volume occupied by red blood cells. If red blood cells are agglutinated and not evenly distributed throughout the blood sample, they may settle more quickly at the bottom of the tube. This can lead to a falsely low hematocrit value.

Answer: Spleen

The spleen is responsible for the “pitting process” for red blood cells (RBCs), which involves the removal of damaged or senescent RBCs from circulation by macrophages within the spleen.

The other options are incorrect:

• Liver: The liver primarily functions in the metabolism of various substances and does not play a significant role in the removal of senescent RBCs.
• Kidney: The kidneys primarily function in the filtration of blood and regulation of electrolytes, but they are not involved in the removal of RBCs from circulation.
• Lymph nodes: Lymph nodes are part of the lymphatic system and are involved in immune responses, but they do not participate in the removal of RBCs from circulation.

Answer: Increase deformability

Spherocytes, unlike normal red blood cells, typically have increased deformability, meaning they are more prone to change shape under stress.

The other options are incorrect:

• Decreased surface to volume: Spherocytes typically have a decreased surface-to-volume ratio compared to normal red blood cells.
• No central pallor: Spherocytes lack central pallor, unlike normal red blood cells, which have a characteristic central area of lighter staining.
• Decreased resistance to hypotonic saline: Spherocytes are known for their increased resistance to hypotonic saline solutions, not decreased resistance.

Answer: Hereditary spherocytosis

Hereditary spherocytosis is associated with an increase in osmotic fragility, meaning that red blood cells from individuals with this disorder are more prone to hemolysis in hypotonic solutions.

The other options are incorrect:

• Iron deficiency anemia: Iron deficiency anemia does not typically result in increased osmotic fragility of red blood cells.
• Hereditary elliptocytosis: Hereditary elliptocytosis is associated with abnormal red blood cell morphology (elliptocytes), but it does not usually lead to increased osmotic fragility.
• Hereditary stomatocytosis: Hereditary stomatocytosis is characterized by the presence of stomatocytes (mouth-shaped red blood cells), but it does not typically result in increased osmotic fragility.

Answer: Normocytic, normochromic

The anemia seen in sickle cell disease is typically normocytic and normochromic, meaning that the size and hemoglobin content of the red blood cells are within normal ranges.

The other options are incorrect:

• Microcytic, normochromic: Microcytic anemia is characterized by small red blood cells, which is not typically observed in sickle cell disease.
• Microcytic, hypochromic: Hypochromic anemia is characterized by red blood cells with decreased hemoglobin content, which is not typically observed in sickle cell disease.
• Normocytic, hypochromic: Normocytic anemia with hypochromia is characterized by normal-sized but pale red blood cells, which is not typically observed in sickle cell disease.
• a

Answer: Hgb A

In individuals with sickle cell trait, the major hemoglobin found in red blood cells is hemoglobin A (Hgb A), which consists of two alpha and two beta globin chains.

The other options are incorrect:

• Hgb S: Hemoglobin S is the abnormal hemoglobin present in individuals with sickle cell disease, not sickle cell trait.
• Hgb F: Hemoglobin F (fetal hemoglobin) is present in small amounts in adults and is not the major hemoglobin found in individuals with sickle cell trait.
• Hgb A2: Hemoglobin A2 is a minor hemoglobin component mainly found in adults, and it is not the major hemoglobin present in individuals with sickle cell trait.

Answer: Fast mobility of Hbg C at pH 8.6

Hemoglobin C typically exhibits slower mobility on electrophoresis at alkaline pH (pH 8.6), unlike hemoglobin A. This is due to the substitution of lysine for glutamic acid at the sixth position of the beta chain.

The other options are incorrect:

• Hgb C crystals: Hgb C disease can lead to the formation of Hgb C crystals within red blood cells.
• Target cells: Target cells are often seen in Hgb C disease due to the altered shape of red blood cells.
• Lysine substituted for glutamic acid at the sixth position of the B-chain: This substitution is characteristic of Hgb C disease and is not an exception.

Answer: Hgb A: 60% Hgb S: 40% Hgb A2: 2%

In sickle cell trait, there is a presence of both hemoglobin A and hemoglobin S. Hemoglobin A is typically higher than hemoglobin S, and there may be a small amount of hemoglobin A2. This electrophoretic pattern is consistent with sickle cell trait.

The other options are incorrect:

• Hgb A: 40% Hgb S: 35% Hgb F: 5%: This pattern does not reflect sickle cell trait, as the percentage of hemoglobin S is higher than expected.
• Hgb A: 0% Hgb A2: 5% Hgb F: 95%: This pattern indicates a high percentage of hemoglobin F, which is not characteristic of sickle cell trait.
• Hgb A: 80% Hgb S: 10% Hgb A2: 10%: While there is a presence of hemoglobin A and hemoglobin S, the proportion of hemoglobin S is too low for sickle cell trait.

Answer: Sickle cell disease

Autosplenectomy is most likely to occur in sickle cell disease due to repeated sickling and subsequent infarction of the spleen, leading to fibrosis and shrinkage (autosplenectomy).

The other options are incorrect:

• Thalassemia major: Thalassemia major typically does not lead to autosplenectomy.
• Hgb C disease: Autosplenectomy is less common in Hgb C disease compared to sickle cell disease.
• Hgb SC disease: Autosplenectomy is less common in Hgb SC disease compared to sickle cell disease.