Hematopathology Practice Questions

Q: What is the characteristic marker for hairy cell leukemia?

CD103. **Explanation:** **Hairy Cell Leukemia (HCL)** is a rare, chronic B-cell lymphoproliferative disorder characterized by the proliferation of mature B-cells with hair-like cytoplasmic projections [1]. **Why CD103 is the correct answer:** CD103 (an alpha-E integrin) is considered the most specific immunophenotypic marker for HCL. The diagnosis is typically confirmed via flow cytometry showing a "bright" expression of mature B-cell markers (CD19, CD20, CD22) along with a specific quartet of markers: **CD103, CD11c, CD25, and annexin A1.** Among these, Annexin A1 is the most specific immunohistochemical marker, while CD103 is the classic flow cytometry hallmark. **Analysis of Incorrect Options:** * **CD30:** A marker for activated lymphocytes; it is the hallmark for **Hodgkin Lymphoma** (Reed-Sternberg cells) and **Anaplastic Large Cell Lymphoma (ALCL)**. * **CD1:** Specifically CD1a is a marker for **Langerhans Cell Histiocytosis (LCH)** and cortical thymocytes. * **CD4:** A marker for **T-helper cells**. It is expressed in T-cell lineages and is relevant in conditions like Mycosis Fungoides or Adult T-cell Leukemia/Lymphoma (ATLL). **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Triad:** Splenomegaly (often massive), Pancytopenia, and "Dry tap" on bone marrow aspiration (due to increased reticulin fibrosis) [1]. * **TRAP Stain:** Historically diagnosed using Tartrate-Resistant Acid Phosphatase (TRAP) positivity. * **Genetic Mutation:** Virtually 100% of cases harbor the **BRAF V600E** mutation. * **Treatment:** Highly sensitive to purine analogs like **Cladribine** (Drug of choice). **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. 612.

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.

Question 1

What is the characteristic marker for hairy cell leukemia?

Accepted Answer

CD103

Answer

CD30

Answer

CD1

Answer

CD4

Question 2

A patient presents with microcytic hypochromic anaemia. Laboratory investigations reveal reduced total serum iron, reduced percentage saturation of serum transferrin, and increased serum ferritin levels. What is the most likely diagnosis?

Accepted Answer

Anaemia of chronic disease

Answer

Iron deficiency anaemia

Answer

Sideroblastic anaemia

Answer

Pernicious anaemia

Question 3

Iron levels are decreased in all of the following conditions except:

Accepted Answer

Sideroblastic anemia

Answer

Anemia due to chronic infection

Answer

Anemia due to gastric ulcer (bleeding ulcer)

Answer

Hookworm anemia

Question 4

Which of the following disorders is least likely to be associated with a prolonged bleeding time?

Accepted Answer

Coagulation factor deficiencies

Answer

Thrombocytopenia

Answer

Platelet dysfunction

Answer

Disseminated Intravascular Coagulation (DIC)

Question 5

What condition is characterized by the presence of leptocytes in blood smears?

Accepted Answer

Thalassemia

Answer

Sickle cell anemia

Answer

Post splenectomy

Answer

Uremia

Question 6

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 7

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 8

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 9

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 10

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

Hematopathology — MCQs

Hematopathology — MCQs

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