Hematopathology — MCQs

Hematopathology Indian Medical PG Practice Questions and MCQs

Question 1381: What is a distinguishing feature of reticulocytes?

A. Slightly larger in size than RBCs
B. Presence of residual RNA and ribosomes (Correct Answer)
C. Mature in bone marrow
D. Constitute approximately 1% of the red cells

Explanation: ***Presence of residual RNA and ribosomes*** - This is the **defining and most distinguishing feature** of reticulocytes that differentiates them from mature red blood cells. - Reticulocytes contain residual **ribosomal RNA** and other organelles that are lost when they mature into erythrocytes. - This residual RNA forms a **reticular (network-like) pattern** when stained with supravital stains like **new methylene blue** or **brilliant cresyl blue**, which is the basis for their name and identification. - The presence of RNA allows for **reticulocyte counting**, an important marker of bone marrow erythropoietic activity. *Slightly larger in size than RBCs* - While reticulocytes may be slightly larger (polychromatophilic appearance), size variation is **not specific** and overlaps significantly with mature RBCs. - Size is not a reliable distinguishing feature and is not used for identification or counting. *Mature in bone marrow* - Reticulocytes are **released from the bone marrow** as immature red cells and complete their maturation in the **peripheral circulation** over 24-48 hours. - They do not fully mature in the bone marrow; their presence in peripheral blood is normal. *Constitute approximately 1% of the red cells* - Normal reticulocyte count is **0.5-2%** (or approximately 1%) of total red blood cells in healthy adults. - This is a **population characteristic** indicating normal erythropoietic activity, not a distinguishing cellular feature.

Question 1382: Shelf life of platelets in a blood bank is

A. 5 days (Correct Answer)
B. 7 days
C. 10 days
D. 21 days

Explanation: **5 days** - Platelets stored at **room temperature (20-24°C)** have a limited shelf life due to the risk of bacterial contamination and metabolic changes. - This short storage period ensures the **viability and function** of platelets for transfusion. *7 days* - A 7-day shelf life was initially proposed but was not widely adopted due to concerns about increased **bacterial growth** and the practical challenges of extended storage at room temperature. - The risk of **bacterial sepsis** significantly increases with longer room temperature storage. *10 days* - This duration is beyond the currently accepted shelf life for platelets, leading to an unacceptably high risk of **bacterial contamination** and reduced therapeutic efficacy. - Storing platelets for 10 days would likely result in an increased incidence of **transfusion-associated sepsis**. *21 days* - A shelf life of 21 days is typical for **red blood cells** when stored at 1-6°C with specific anticoagulants, but it is far too long for platelets. - Platelets stored for this duration at room temperature would be significantly **non-viable** and pose a severe risk of bacterial infection.

Question 1383: Which of the following is NOT seen in polycythemia vera?

A. Increased erythropoietin (Correct Answer)
B. Intrinsic abnormality of hematopoietic precursors
C. Erythropoietin independent growth of red cell progenitors
D. Most common cause of primary polycythemia

Explanation: ***Increased erythropoietin*** - In polycythemia vera, patients usually exhibit **low erythropoietin levels** due to feedback inhibition from increased red blood cell mass. - The condition is driven by a **myeloproliferative disorder** [2], not by increased erythropoietin stimulation. *Most common cause of polycythemia* - This option is incorrect because polycythemia vera is specifically a type of **primary polycythemia** [1], rather than the most common cause, which is often **secondary causes** such as hypoxia or abnormal erythropoietin production. - Other causes including chronic lung disease or renal tumors are more prevalent sources of increased red blood cell production. *Intrinsic abnormality of hematopoietic precursors* - While polycythemia vera indeed involves an **abnormality in hematopoietic stem cells** [1], it is not the only mechanism leading to polycythemia; many cases have secondary causes. - Hence, this option misrepresents the specific and more accurate characterization of polycythemia vera. *Erythropoietin independent growth of red cell progenitors* - Polycythemia vera is associated with **erythropoietin-independent** proliferation of hematopoietic cells [2], which is characteristic of the condition due to mutations in **JAK2** [2,3]. - This accurately reflects a significant feature of the disease, aligning closely with the pathophysiology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 663-664. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 626-627.

Question 1384: Which of the following statements is true regarding the Duffy Fy(a-b-) blood group?

A. lacks H- antigen
B. lacks A-antigen
C. All of the options
D. lacks Fy(b) antigen (Correct Answer)

Explanation: ***lacks Fy(b) antigen*** - The **Duffy Fy(a-b-)** phenotype indicates absence of both Fya and Fyb antigens on red blood cells. - Since the phenotype is **Fy(a-b-)**, it definitively lacks the **Fyb antigen** (indicated by the "b-" notation). - This phenotype is common in people of **African descent** and confers natural **resistance to Plasmodium vivax malaria**, as these antigens serve as receptors for the parasite to enter RBCs. *lacks H- antigen* - The **H antigen** belongs to the **H/h blood group system** and is a precursor to A and B antigens in the ABO system. - The absence of H antigen (Bombay phenotype - Oh) is completely **unrelated to the Duffy blood group system**. - Duffy antigens are on the **DARC (Duffy Antigen Receptor for Chemokines)** protein, distinct from the H antigen. *lacks A-antigen* - The **A antigen** is part of the **ABO blood group system** and defines blood types A and AB. - The Duffy blood group system is **genetically and structurally independent** from the ABO system. - Having Fy(a-b-) phenotype does not affect A antigen expression. *All of the options* - This is incorrect because the Duffy Fy(a-b-) phenotype **specifically refers only to the absence of Duffy antigens** (Fya and Fyb). - It has **no relationship** with A, B, or H antigens, which belong to different blood group systems controlled by different genes on different chromosomes.

Question 1385: Which antigen is tested in routine Rh typing?

A. C antigen
B. D antigen (Correct Answer)
C. A antigen
D. B antigen

Explanation: ***D antigen*** - Routine Rh typing specifically tests for the **D antigen**, which determines the Rh status of an individual as Rh-positive or Rh-negative [1]. - The presence of the **D antigen** is crucial for blood transfusions and pregnancy management [1]. *A antigen* - The **A antigen** is tested in the context of the ABO blood group system, not specifically for Rh typing. - It does not provide information regarding the Rh factor which is critical in blood compatibility. *C antigen* - Similar to the **A antigen**, the **C antigen** is part of the broader Rh system but is not routinely assessed in standard Rh typing. - Its testing is typically reserved for specific clinical scenarios involving Rh incompatibility. *B antigen* - The **B antigen** pertains to the ABO blood group and does not relate to the Rh factor or routine Rh typing. - Rh typing is solely focused on the **presence of the D antigen** to determine the Rh status. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 627-628.

Question 1386: The most common translocation seen in patients with Multiple Myeloma is:

A. t(14;16)
B. t(4;14)
C. t(11;14) (Correct Answer)
D. t(14;20)

Explanation: ***t(11;14)*** - This translocation is the **most common cytogenetic abnormality** found in patients with multiple myeloma, occurring in approximately 15-20% of cases. - It results in the juxtaposition of the **IgH gene on chromosome 14** with the **cyclin D1 gene on chromosome 11**, leading to overexpression of cyclin D1. *t(4;14)* - This translocation, occurring in about 5-10% of patients, is associated with a **poor prognosis** in multiple myeloma. - It involves the IgH gene on chromosome 14 and the **FGFR3 and MMSET genes on chromosome 4**, leading to their upregulation. *t(14;16)* - This translocation is also associated with a **poor prognosis** and is less common than t(11;14) or t(4;14), found in about 2-5% of cases. - It involves the **IgH gene on chromosome 14** and the **c-MAF gene on chromosome 16**, leading to overexpression of c-MAF. *t(14;20)* - This translocation is **rarely observed** in multiple myeloma patients, typically occurring in less than 1% of cases. - It involves the **IgH gene on chromosome 14** and the **MAFB gene on chromosome 20**, which can also contribute to disease progression.

Question 1387: What is the Thomsen Friedenreich phenomenon?

A. Agglutination of red blood cells by all blood group sera
B. Agglutination of red blood cells by anti-T antibodies
C. Association with certain malignancies
D. Exposure of cryptic T-antigen on red blood cells (Correct Answer)

Explanation: ***Exposure of cryptic T-antigen on red blood cells*** - The Thomsen Friedenreich phenomenon, also known as **T-activation**, occurs when bacterial enzymes (neuraminidase) remove N-acetylneuraminic acid (sialic acid) residues from red cell surface glycoproteins, **unmasking the cryptic T-antigen** (Thomsen-Friedenreich antigen). - This unmasking leads to the red blood cells becoming agglutinable by naturally occurring **anti-T antibodies** present in almost all adult human sera, resulting in polyagglutination. - The T-antigen is not newly synthesized but is **pre-existing and cryptic**, hidden beneath sialic acid residues until exposed by bacterial neuraminidase activity. *Agglutination of red blood cells by anti-T antibodies* - While agglutination by anti-T antibodies is a *consequence* of the Thomsen Friedenreich phenomenon, it is not the phenomenon itself. The phenomenon describes the underlying cellular change - the **exposure of the cryptic T-antigen**. - This polyagglutination occurs because anti-T antibodies are naturally present in nearly all adult human sera. *Agglutination of red blood cells by all blood group sera* - The Thomsen Friedenreich phenomenon specifically involves agglutination by **anti-T antibodies**, which are naturally occurring and widely present, but it does not mean agglutination by *all* blood group sera (e.g., anti-A, anti-B, anti-D won't cause agglutination based on T-activation alone). - The T-antigen is distinct from the **ABO blood group antigens** and other blood group systems. *Association with certain malignancies* - While T-antigen (Tn antigen) can be expressed on certain **malignant cells** (tumor-associated antigen) and is relevant in cancer immunology, this is a separate clinical context from the Thomsen Friedenreich phenomenon in **blood banking** and transfusion medicine. - The Thomsen Friedenreich phenomenon primarily refers to the **acquired exposure** of cryptic T-antigen on red blood cells due to bacterial neuraminidase action, typically seen in infections or bacterial contamination.

Question 1388: Which of the following statements is false regarding hereditary spherocytosis?

A. Defect in ankyrin
B. Reticulocytosis
C. Decreased MCHC (Correct Answer)
D. Normal to increased MCV

Explanation: ***Decreased MCHC*** - Hereditary spherocytosis typically presents with an **increased MCHC** due to the spherocytes being more concentrated. - MCHC is a measure of the hemoglobin concentration in red blood cells, and in spherocytosis, this value is often elevated rather than decreased. *Defect in ankyrin* - This is a true statement; hereditary spherocytosis is associated with a defect in **ankyrin**, a protein that helps maintain the cell's membrane structure [2]. - Mutations in ankyrin lead to instability of the red blood cell membrane, resulting in spherocyte formation [2]. *Decreased MCV* - In hereditary spherocytosis, MCV is often **normal or slightly increased**, as it reflects the volume of red blood cells, which can be misinterpreted due to the presence of spherocytes. - Spherocytes are smaller cells, which can mistakenly suggest a falsely decreased MCV if not properly interpreted [1]. *Reticulocytosis* - This condition typically presents with **reticulocytosis** as a response to hemolysis, indicating the bone marrow is producing more red blood cells to compensate [1]. - The presence of reticulocytosis is a common finding in hereditary spherocytosis due to increased destruction of spherocytes. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-641.

Question 1389: Which is not a feature of paroxysmal nocturnal hemoglobinuria?

A. Thrombocytopenia
B. Hemolysis
C. Increased LAP score (Correct Answer)
D. Thrombosis

Explanation: ***Increased LAP score*** - In paroxysmal nocturnal hemoglobinuria, the **LAP score** is typically **low** due to ineffective hematopoiesis and not elevated. - The presence of a low LAP score is inconsistent with the features of this condition, making it the correct choice. *Thrombosis* - Paroxysmal nocturnal hemoglobinuria is **associated with a high risk of thrombosis**, particularly in the **venous system** [2]. - This is due to **increased platelet activation** and excessive thrombin generation resulting from hemolysis. *Hemolysis* - **Hemolysis** is a hallmark feature of paroxysmal nocturnal hemoglobinuria, where there is **destruction of red blood cells** [2,3]. - Patients often present with signs of hemolytic anemia including **elevated bilirubin** and **low haptoglobin** levels. *Thrombocytopenia* - **Thrombocytopenia** is a common finding in paroxysmal nocturnal hemoglobinuria due to **expanded consumption** of platelets during episodes of hemolysis. - This can lead to an **increased risk of bleeding** in affected patients. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 601-602. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 650-651.

Question 1390: MALT lymphoma is positive for which of the following markers?

A. CD20 (Correct Answer)
B. CD19
C. CD43
D. CD5

Explanation: ***CD20*** - MALT lymphoma is a type of **B-cell non-Hodgkin lymphoma**, and CD20 is a **pan B-cell marker consistently expressed** in MALT lymphomas. - CD20 positivity is **crucial for diagnosis** and is the **primary therapeutic target** for anti-CD20 monoclonal antibody therapy (Rituximab). - In diagnostic practice, **CD20 is the most important B-cell marker** for identifying MALT lymphoma and guiding treatment decisions. *CD19* - CD19 is also a **pan B-cell marker** and is **typically positive in MALT lymphoma** along with CD20. - However, in the context of this question, **CD20 is the preferred answer** because it is the **standard diagnostic marker emphasized in clinical practice** and the **primary therapeutic target**. - Both markers are positive, but CD20 has greater **clinical and therapeutic significance** in MALT lymphoma management. *CD43* - CD43 is primarily a **T-cell and myeloid marker**, but can show **aberrant expression in 40-50% of MALT lymphomas**. - While it may be positive in some cases, it is **not a defining B-cell lineage marker** and is not used as a primary diagnostic criterion for MALT lymphoma. - Its variable expression makes it **less reliable** than consistent B-cell markers like CD20. *CD5* - CD5 is typically associated with **T-cells** and certain B-cell lymphomas, particularly **chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL)** and **mantle cell lymphoma**. - **MALT lymphoma is characteristically CD5-negative**, which is an important feature for **differentiating it from CD5+ B-cell lymphomas**.

Practice by Chapter

Anemias: Classification and Approach

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Hemolytic Anemias

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Myeloproliferative Neoplasms

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Myelodysplastic Syndromes

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Acute Leukemias

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Chronic Leukemias

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Lymphomas and Lymphoid Neoplasms

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Plasma Cell Disorders

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Bleeding Disorders

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Thrombotic Disorders

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