Hematopathology Practice Questions

Q: What is the shelf life of gamma-irradiated packed red blood cells (pRBCs)?

28 days. **Explanation:** The shelf life of gamma-irradiated packed red blood cells (pRBCs) is **28 days** from the date of irradiation or the original expiry date of the unit, whichever comes first. **Why 28 days?** Gamma irradiation (usually 25 Gy) is performed to prevent **Transfusion-Associated Graft-Versus-Host Disease (TA-GVHD)** by inactivating donor T-lymphocytes. However, the radiation damages the RBC membrane, leading to increased potassium leakage (hyperkalemia) and a decrease in ATP and 2,3-DPG levels. This accelerated metabolic decay reduces the post-transfusion survival of the RBCs, necessitating a shortened shelf life of 28 days to ensure clinical efficacy and safety. **Analysis of Options:** * **A. 21 days:** This is the shelf life of whole blood or pRBCs collected in **CPD** (Citrate Phosphate Dextrose) anticoagulant without additive solutions. * **C. 35 days:** This is the standard shelf life for pRBCs collected in **CPDA-1** (Citrate Phosphate Dextrose Adenine) anticoagulant. * **D. 42 days:** This is the shelf life for pRBCs stored with **additive solutions** like SAGM (Saline Adenine Glucose Mannitol) or ADSOL. **High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Irradiation is mandatory for immunocompromised patients (e.g., Hodgkin lymphoma, bone marrow transplant), intrauterine transfusions, and directed donations from first-degree relatives. * **Dose:** The central dose of irradiation should be **25 Gray (Gy)**, with no part receiving less than 15 Gy. * **Potassium Warning:** Because irradiation increases extracellular potassium, irradiated units should be transfused immediately (or within 24 hours) in neonatal or large-volume exchange transfusions to avoid cardiac arrhythmias.

Q: Paroxysmal nocturnal hemoglobinuria is due to what type of defect?

Acquired red cell defect. **Explanation:** **Paroxysmal Nocturnal Hemoglobinuria (PNH)** is a unique hematological disorder characterized by an **acquired intracorpuscular defect**. **1. Why "Acquired Red Cell Defect" is correct:** PNH is caused by a somatic mutation in the **PIGA gene** (Phosphatidylinositol Glycan class A) within a hematopoietic stem cell. This mutation is not inherited (congenital) but occurs during an individual's lifetime. The mutation leads to a deficiency of **GPI-anchored proteins** on the cell membrane, specifically **CD55 (DAF)** and **CD59 (MIRL)**. These proteins normally protect red cells from complement-mediated lysis. Their absence makes the RBCs abnormally sensitive to complement, leading to intravascular hemolysis. **2. Why other options are incorrect:** * **Congenital red cell defect:** Although PNH is a genetic mutation, it is **somatic**, not germline. It is not passed from parent to offspring, unlike Hereditary Spherocytosis or Thalassemia. * **Autoimmune defect:** Hemolysis in PNH is mediated by the **alternative complement pathway**, not by antibodies (immunoglobulins). Therefore, the Direct Coombs Test is characteristically **negative**. * **Lead poisoning:** This causes microcytic anemia by inhibiting enzymes in the heme synthesis pathway (ALAD and Ferrochelatase) and is associated with basophilic stippling, not complement-mediated lysis. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of PNH:** Hemolytic anemia, Pancytopenia, and Venous thrombosis (often in unusual sites like the hepatic vein—Budd-Chiari syndrome). * **Gold Standard Diagnosis:** Flow cytometry showing absence of CD55 and CD59. * **Treatment:** **Eculizumab** (a monoclonal antibody against Complement C5) is the drug of choice. * **Association:** PNH is closely linked with **Aplastic Anemia** and may transform into Acute Myeloid Leukemia (AML).

Q: What is the primary laboratory test used to screen for Beta-thalassemia trait?

Hemoglobin A2 (HbA2). The primary laboratory screening and diagnostic test for **Beta-thalassemia trait (minor)** is the measurement of **Hemoglobin A2 (HbA2)** levels, typically performed via High-Performance Liquid Chromatography (HPLC) or electrophoresis [1]. In Beta-thalassemia, there is a reduced synthesis of $\beta$-globin chains [2]. To compensate, the body increases the production of $\delta$-chains, which combine with $\alpha$-chains to form HbA2 ($\alpha_2\delta_2$) [3]. A **HbA2 level >3.5%** is the diagnostic hallmark of Beta-thalassemia trait. **Analysis of Incorrect Options:** * **B. Hemoglobin F (HbF):** While HbF may be slightly elevated in the trait (1–5%), it is significantly elevated in Beta-thalassemia *major*. It is not the primary screening marker for the trait. * **C. Osmotic Fragility Test:** This test is primarily used to diagnose **Hereditary Spherocytosis** (where fragility is increased). In thalassemia, cells are hypochromic and microcytic, actually showing *decreased* osmotic fragility. * **D. Coombs Test:** This is used to detect antibodies in **Autoimmune Hemolytic Anemia (AIHA)**. Thalassemia is a quantitative hemoglobinopathy, not an immune-mediated process. **High-Yield Clinical Pearls for NEET-PG:** * **Mentzer Index:** Used to differentiate Iron Deficiency Anemia (IDA) from Thalassemia trait. **MCV/RBC count 13** suggests IDA. * **Peripheral Smear:** Characterized by microcytic hypochromic anemia with **target cells** and basophilic stippling. * **NESTROFT:** (Naked Eye Single Tube Red Cell Osmotic Fragility Test) is often used as a cost-effective mass screening tool in field studies, but **HPLC (HbA2)** remains the gold standard for confirmation.

Q: All of the following are true regarding Anemia of Chronic Disease, except?

Decreased ferritin. **Explanation:** Anemia of Chronic Disease (ACD), also known as Anemia of Inflammation, is primarily mediated by **Hepcidin**, an acute-phase reactant produced by the liver in response to inflammatory cytokines (especially IL-6) [1]. **Why Option B is the Correct Answer (The "Except" statement):** In ACD, **Serum Ferritin is typically increased or normal**, not decreased. Ferritin acts as an acute-phase reactant; inflammation causes the body to sequester iron within storage sites (macrophages and hepatocytes) to withhold it from potential pathogens. A **decreased ferritin** is the hallmark of **Iron Deficiency Anemia (IDA)** [1], making this the false statement regarding ACD [2]. **Analysis of Incorrect Options:** * **Option A (Decreased serum iron):** True. Hepcidin causes the degradation of ferroportin channels, preventing iron release from macrophages and absorption from the gut, leading to low circulating serum iron (hypoferremia) [1]. * **Option C (Decreased TIBC):** True. In states of chronic inflammation, the body downregulates the synthesis of Transferrin (measured as TIBC) to limit iron availability [1]. This helps differentiate ACD from IDA (where TIBC is increased) [2]. * **Option D (Increased bone marrow iron):** True. Because iron is "trapped" inside the reticuloendothelial system (macrophages) and cannot be utilized for erythropoiesis, bone marrow aspirate stained with Prussian blue shows abundant iron stores. **High-Yield Clinical Pearls for NEET-PG:** * **Pathophysiology:** High Hepcidin → Low Ferroportin → Iron Sequestration [1]. * **Morphology:** Usually Normocytic Normochromic; can become Microcytic Hypochromic in long-standing cases [1]. * **Gold Standard Diagnosis:** Bone marrow iron staining (Prussian Blue), though rarely done clinically. * **Key Differentiator:** The **Soluble Transferrin Receptor (sTfR)** index is normal in ACD but elevated in IDA [2].

Q: An elevated White Blood Cell (WBC) count is seen in all of the following conditions except?

Typhoid. The correct answer is **Typhoid (Option A)**. In clinical hematology, most bacterial infections cause leukocytosis (elevated WBC count) [3]. However, Typhoid fever (Enteric fever) is a classic exception. It typically presents with **leukopenia** (decreased WBC count) or a normal WBC count with a relative lymphocytosis. This occurs due to the sequestration of leukocytes in the spleen and bone marrow depression by the *Salmonella typhi* endotoxin [2]. **Analysis of other options:** * **Pertussis (Option B):** Unlike most bacterial infections that cause neutrophilia, *Bordetella pertussis* causes a marked **lymphocytic leukocytosis** [1]. This is due to "pertussis toxin," which prevents lymphocytes from leaving the blood and entering the lymph nodes. * **Lymphoreticular malignancy (Option C):** Conditions like Chronic Lymphocytic Leukemia (CLL) or lymphomas in the leukemic phase are characterized by the uncontrolled proliferation of white cells, leading to significantly elevated WBC counts [1]. * **Tuberculosis (Option D):** TB is a chronic granulomatous infection that typically presents with mild to moderate leukocytosis, often with an increase in monocytes or lymphocytes [1], [3]. In cases of miliary TB, a "leukemoid reaction" (WBC >50,000/µL) can sometimes occur. **High-Yield Clinical Pearls for NEET-PG:** * **Leukopenia in Infections:** Common causes include Typhoid [2], Brucellosis, Kala-azar, and viral infections (like Dengue or HIV). * **Eosinopenia:** A characteristic finding in the early stages of Typhoid fever (disappearance of eosinophils). * **Leukemoid Reaction:** Defined as a reactive increase in WBC count >50,000/µL. It is commonly seen in severe infections (Sepsis, TB) [3] or acute hemolysis, mimicking leukemia but with a high Leukocyte Alkaline Phosphatase (LAP) score.

Q: Acute myeloid leukemia (AML) is characterized by which of the following findings?

Auer rods. **Explanation:** **Acute Myeloid Leukemia (AML)** is a clonal proliferation of myeloid precursors (blasts) in the bone marrow. The presence of **Auer rods** is a pathognomonic hallmark of AML [1]. These are needle-like, azurophilic cytoplasmic inclusions formed by the crystallization of fused primary granules (lysosomes) containing **myeloperoxidase (MPO)** [2]. They are most commonly seen in the M1, M2, M3 (APML), and M4 subtypes of the FAB classification. **Analysis of Incorrect Options:** * **A. Philadelphia chromosome [t(9;22)]:** This is the hallmark of **Chronic Myeloid Leukemia (CML)**, involving the *BCR-ABL1* fusion gene. While it can occur in some cases of B-ALL or AML (as a poor prognostic marker), it is not a defining characteristic of AML. * **C. Hemolytic anemia:** While AML patients present with anemia due to bone marrow infiltration (myelophthisis), it is typically **normocytic normochromic** and non-hemolytic. * **D. Dohle bodies:** These are light blue, peripheral cytoplasmic inclusions (remnants of rough endoplasmic reticulum) found in **neutrophils** during states of inflammation, infection, or burns (toxic changes), rather than in leukemic blasts. **High-Yield Clinical Pearls for NEET-PG:** * **M3 Subtype (APML):** Characterized by "faggot cells" (bundles of Auer rods) and a high risk of **DIC** due to the release of procoagulants [1]. * **Diagnosis:** According to WHO criteria, AML requires **≥20% blasts** in the peripheral blood or bone marrow. * **Cytochemistry:** AML blasts are typically **MPO positive** and Sudan Black B positive, helping differentiate them from ALL. **References:** [1] 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, p. 620. [2] 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. 621-622.

Question 1

What is the shelf life of gamma-irradiated packed red blood cells (pRBCs)?

Accepted Answer

28 days

Answer

21 days

Answer

35 days

Answer

42 days

Question 2

Paroxysmal nocturnal hemoglobinuria is due to what type of defect?

Accepted Answer

Acquired red cell defect

Answer

Congenital red cell defect

Answer

Autoimmune defect

Answer

Lead poisoning

Question 3

What is the primary laboratory test used to screen for Beta-thalassemia trait?

Accepted Answer

Hemoglobin A2 (HbA2)

Answer

Hemoglobin F (HbF)

Answer

Osmotic fragility test

Answer

Coombs test

Question 4

A biopsy of a nasopharyngeal mass in a 30-year-old man shows a plasma cell proliferation. Serum electrophoresis reveals a monoclonal IgG spike. Bone marrow examination does not show plasma cell proliferation, and skeletal x-rays are negative for lesions. What is the most likely diagnosis?

Accepted Answer

Plasmacytoma

Answer

Heavy chain disease

Answer

Monoclonal gammopathy of undetermined significance

Answer

Multiple myeloma

Question 5

Which of the following is a differentiating feature between Hodgkin's lymphoma and non-Hodgkin's lymphoma?

Accepted Answer

Presence of Reed-Sternberg cells

Answer

Presence of B symptoms (fever, night sweats, weight loss)

Answer

Generalized lymphadenopathy

Answer

Predominance in the elderly

Question 6

All of the following are true regarding Anemia of Chronic Disease, except?

Accepted Answer

Decreased ferritin

Answer

Decreased serum iron

Answer

Decreased total iron-binding capacity

Answer

Increased bone marrow iron

Question 7

Thrombocytosis is seen in which of the following conditions?

Accepted Answer

Haemolytic anaemia

Answer

Osteopetrosis

Answer

Disseminated intravascular coagulation

Answer

Thiazide therapy

Question 8

An elevated White Blood Cell (WBC) count is seen in all of the following conditions except?

Accepted Answer

Typhoid

Answer

Pertussis

Answer

Lymphoreticular malignancy

Answer

Tuberculosis

Question 9

Acute myeloid leukemia (AML) is characterized by which of the following findings?

Accepted Answer

Auer rods

Answer

Philadelphia chromosome

Answer

Hemolytic anemia

Answer

Dohle bodies

Question 10

Eosin-5-maleimide flow cytometry is used for the diagnosis of which condition?

Accepted Answer

Hereditary spherocytosis

Answer

Glucose-6-phosphate dehydrogenase deficiency

Answer

Sickle cell anemia

Answer

Alpha thalassemia

Hematopathology — MCQs

Hematopathology — MCQs

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