Hematopathology — MCQs
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Which statement is true regarding Hemophilia A?
A 42-year-old man presents with chronic fatigue. His hemoglobin is 11.5 g/dL, and the blood film shows hypochromic and microcytic red blood cells. Laboratory findings include increased serum iron, normal total iron-binding capacity (TIBC), increased ferritin, and decreased HbA2. What is the most likely diagnosis for this patient's hypochromic microcytic anemia?
Leukocytosis is seen in all conditions except?
Schistocytes are seen in:
All of the following are true of disseminated intravascular coagulation (DIC) except:
In which of the following conditions does neutropenia occur?
Which is the most common cause of spherocytosis?
Which investigation can distinguish between pregnancy-acquired hemophilia A and lupus anticoagulant?
In G6PD deficiency, which red blood cells are more prone to hemolysis?
Hemoglobin electrophoresis is used as a confirmatory test in which of the following anemias?
Hematopathology Indian Medical PG Practice Questions and MCQs
Question 431: Which statement is true regarding Hemophilia A?
- A. Increased bleeding time
- B. Increased prothrombin time
- C. Increased partial thromboplastin time (Correct Answer)
- D. Increased platelet count
Explanation: **Explanation:** **Hemophilia A** is an X-linked recessive bleeding disorder characterized by a deficiency of **Coagulation Factor VIII** [1], [4]. 1. **Why Option C is Correct:** Factor VIII is a crucial component of the **intrinsic pathway** of the coagulation cascade [2]. The **Activated Partial Thromboplastin Time (aPTT)** measures the integrity of the intrinsic and common pathways (Factors XII, XI, IX, VIII, X, V, II, and I) [2]. Therefore, a deficiency in Factor VIII leads to a prolonged/increased aPTT. 2. **Why Other Options are Incorrect:** * **Option A (Bleeding Time):** Bleeding time (BT) evaluates **primary hemostasis** (platelet function and vessel wall integrity). In Hemophilia A, primary hemostasis is intact; the defect lies in secondary hemostasis (clot stabilization). Thus, BT is **normal**. * **Option B (Prothrombin Time):** PT measures the **extrinsic pathway** (Factor VII). Since Factor VIII is not part of this pathway, the PT remains **normal**. * **Option D (Platelet Count):** Hemophilia is a coagulation factor deficiency, not a quantitative platelet disorder. The platelet count is **normal**. **High-Yield Clinical Pearls for NEET-PG:** * **Inheritance:** X-linked recessive (affects males; females are typically asymptomatic carriers) [1], [4]. * **Clinical Presentation:** Characterized by deep tissue bleeding, most notably **hemarthrosis** (bleeding into joints, commonly the knee) and hematomas [1], [3]. * **Mixing Study:** In Hemophilia A, the prolonged aPTT **corrects** when the patient's plasma is mixed with normal plasma (distinguishing it from Factor VIII inhibitors/antibodies). * **Treatment:** Recombinant Factor VIII replacement or Emicizumab (a bispecific antibody) [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 670-671. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 128-130. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 623-624. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 622-623.
Question 432: A 42-year-old man presents with chronic fatigue. His hemoglobin is 11.5 g/dL, and the blood film shows hypochromic and microcytic red blood cells. Laboratory findings include increased serum iron, normal total iron-binding capacity (TIBC), increased ferritin, and decreased HbA2. What is the most likely diagnosis for this patient's hypochromic microcytic anemia?
- A. Iron deficiency anemia
- B. Beta-thalassemia trait
- C. Anemia of chronic disease
- D. Sideroblastic anemia (Correct Answer)
Explanation: ### Explanation **Correct Answer: D. Sideroblastic Anemia** The hallmark of **Sideroblastic Anemia** is a defect in heme synthesis despite the presence of adequate iron. This leads to iron overload within the mitochondria of developing erythroblasts, forming "ringed sideroblasts." * **Biochemical Profile:** Because iron cannot be incorporated into protoporphyrin, it accumulates in the body. This results in **increased serum iron**, **increased ferritin** (reflecting high stores), and **increased transferrin saturation**. * **Morphology:** Despite the high iron levels, the inability to produce heme results in **hypochromic microcytic** RBCs on the peripheral smear [1]. --- ### Why Other Options are Incorrect: * **A. Iron Deficiency Anemia (IDA):** This is the most common cause of microcytic anemia, but it is characterized by **decreased** serum iron and ferritin, and **increased** TIBC [2]. * **B. Beta-Thalassemia Trait:** While it presents with microcytic anemia, serum iron and ferritin are typically **normal or slightly elevated**. Crucially, HbA2 is **increased** (>3.5%) in Beta-thalassemia trait, whereas this patient has decreased HbA2 [5]. * **C. Anemia of Chronic Disease (ACD):** In ACD, iron is "trapped" in macrophages [3]. This leads to **decreased** serum iron and **decreased** TIBC, though ferritin is usually increased (as an acute-phase reactant) [4]. --- ### NEET-PG High-Yield Pearls: * **Gold Standard Diagnosis:** Bone marrow examination with **Prussian Blue stain** showing **Ringed Sideroblasts** (iron-laden mitochondria encircling >1/3rd of the nucleus). * **Common Causes:** Alcohol (most common), Lead poisoning, Vitamin B6 (Pyridoxine) deficiency, and drugs like Isoniazid (INH). * **Key Enzyme:** The most common hereditary form is an X-linked defect in **ALAS-2** (Aminolevulinate synthase). * **Treatment Tip:** Some patients respond to high doses of **Vitamin B6 (Pyridoxine)**. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 659-660. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 658-659. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 660-662. [5] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 587-588.
Question 433: Leukocytosis is seen in all conditions except?
- A. Brucellosis
- B. Acute MI
- C. Typhoid (Correct Answer)
- D. Diphtheria
Explanation: **Explanation:** The correct answer is **Typhoid (Option C)**. **1. Why Typhoid is the correct answer:** In most bacterial infections, the body responds with **leukocytosis** (increased WBC count), specifically neutrophilia [2]. However, **Typhoid fever** (caused by *Salmonella typhi*) is a classic exception. It characteristically presents with **leukopenia** (decreased WBC count) [1] and **relative lymphocytosis**. This occurs because the bacteria invade the Peyer's patches and the reticuloendothelial system, leading to bone marrow suppression and the sequestration of white cells. **2. Analysis of Incorrect Options:** * **Brucellosis (Option A):** While chronic brucellosis can sometimes show a normal or low count, acute brucellosis typically presents with a mild to moderate **leukocytosis** or a normal count with lymphocytosis. In the context of this competitive question, Typhoid is the more definitive cause of leukopenia. * **Acute MI (Option B):** Myocardial infarction causes sterile inflammation due to tissue necrosis. This triggers a systemic inflammatory response, leading to **neutrophilic leukocytosis**, usually appearing within 24 hours of the insult [2], [3]. * **Diphtheria (Option C):** As an acute bacterial infection caused by *Corynebacterium diphtheriae*, it induces a standard inflammatory response resulting in **leukocytosis** [3]. **3. NEET-PG High-Yield Pearls:** * **Infections causing Leukopenia:** Typhoid, Paratyphoid, Brucellosis (sometimes), Kala-azar, Viral infections (Influenza, Measles, Mumps), and overwhelming Sepsis [1]. * **Eosinopenia:** A classic finding in the early stages of **Typhoid fever** and **Cushing’s syndrome**. * **Basophilia:** Most commonly associated with **Chronic Myeloid Leukemia (CML)** [2]. * **Leukemoid Reaction:** An extreme leukocytosis (>50,000/mm³) seen in severe infections or inflammation, which must be differentiated from leukemia using the **LAP (Leukocyte Alkaline Phosphatase) score**, which is high in leukemoid reactions but low in CML. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 110-111. [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, p. 592. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 580-581.
Question 434: Schistocytes are seen in:
- A. Hereditary spherocytosis
- B. Thalassemia
- C. Microangiopathy (Correct Answer)
- D. Sickle cell anemia
Explanation: **Explanation:** **Schistocytes** (also known as fragmented cells or helmet cells) are the hallmark of **Microangiopathic Hemolytic Anemia (MAHA)** [1]. The underlying mechanism involves the mechanical shearing of red blood cells (RBCs) as they pass through small blood vessels partially obstructed by fibrin strands or platelet thrombi [2]. This "physical trauma" to the RBC membrane results in the characteristic fragmented shapes. Common clinical conditions include TTP, HUS, DIC, and prosthetic heart valves [1]. **Analysis of Options:** * **Hereditary Spherocytosis:** Characterized by **Spherocytes** (small, dark, dense RBCs lacking central pallor). This is due to a molecular defect in membrane proteins (Ankyrin/Spectrin) causing membrane loss, not mechanical fragmentation. * **Thalassemia:** Characterized by **Target cells** (codocytes) and microcytic hypochromic anemia. The pathology involves a quantitative defect in globin chain synthesis. * **Sickle Cell Anemia:** Characterized by **Sickle cells** (drepanocytes) formed due to the polymerization of Hemoglobin S under deoxygenated conditions. **NEET-PG High-Yield Pearls:** * **Bite Cells & Degmacytes:** Seen in G6PD deficiency (due to splenic macrophage removal of Heinz bodies) [3]. * **Echinocytes (Burr Cells):** Associated with Uremia. * **Acanthocytes (Spur Cells):** Associated with Abetalipoproteinemia and Liver disease. * **Dacrocytes (Teardrop Cells):** Classic finding in Primary Myelofibrosis (extramedullary hematopoiesis). * **Basophilic Stippling:** High-yield association with Lead poisoning and Sideroblastic anemia. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 667-668. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 540-541. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 642-643.
Question 435: All of the following are true of disseminated intravascular coagulation (DIC) except:
- A. Platelet aggregation
- B. Fibrin deposition in microcirculation
- C. Decreased fibrin degradation products (Correct Answer)
- D. Release of tissue factor
Explanation: ### Explanation Disseminated Intravascular Coagulation (DIC) is a thrombo-hemorrhagic disorder characterized by the systemic activation of the coagulation cascade. **Why Option C is the correct answer (The "Except"):** In DIC, the widespread formation of fibrin clots triggers an intense secondary **fibrinolysis**. Plasmin cleaves fibrin and fibrinogen, leading to an **increase** in Fibrin Degradation Products (FDPs) and **D-dimers** [1]. Therefore, "decreased" FDPs is incorrect; elevated levels are a hallmark diagnostic feature of DIC [2]. **Analysis of Incorrect Options:** * **Option A (Platelet aggregation):** Systemic activation of the coagulation pathway leads to massive platelet consumption and aggregation as they are trapped within microthrombi [3]. This results in the characteristic **thrombocytopenia** seen in these patients [2]. * **Option B (Fibrin deposition):** The core pathology of DIC involves the "disseminated" formation of fibrin thrombi within the microvasculature (capillaries and arterioles) [4], which can lead to multi-organ dysfunction. * **Option D (Release of tissue factor):** This is the most common trigger for DIC. Tissue factor (Factor III) is released into the circulation due to trauma, obstetric complications, or expressed on monocytes/endothelial cells during sepsis (via cytokines like TNF and IL-1), initiating the extrinsic pathway [3]. **High-Yield Facts for NEET-PG:** * **Peripheral Smear:** Shows **Schistocytes** (fragmented RBCs) due to microangiopathic hemolytic anemia (MAHA) [2]. * **Coagulation Profile:** Prolonged PT, aPTT, and Thrombin Time (TT); decreased Fibrinogen; and elevated D-dimer (most specific) [2]. * **Most Common Cause:** Sepsis (Gram-negative organisms). * **Morphology:** Look for **Waterhouse-Friderichsen syndrome** (adrenal hemorrhage) and **Kasabach-Merritt syndrome** (giant hemangiomas) in related clinical vignettes [4]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 151-152. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 625-626. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 671-672. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 672-673.
Question 436: In which of the following conditions does neutropenia occur?
- A. Vasculitis
- B. Myeloproliferative neoplasm
- C. Exercise
- D. Aplastic Anemia (Correct Answer)
Explanation: **Explanation:** **Correct Answer: D. Aplastic Anemia** **Mechanism:** Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1,500 cells/µL [4]. **Aplastic anemia** is characterized by bone marrow failure resulting from the replacement of hematopoietic stem cells with fat [2]. This leads to **pancytopenia** (anemia, leukopenia/neutropenia, and thrombocytopenia). The underlying pathophysiology usually involves T-cell mediated autoimmune destruction of multipotent stem cells, leading to decreased production of all myeloid lineages [1], [3]. **Analysis of Incorrect Options:** * **A. Vasculitis:** Systemic inflammatory conditions like vasculitis typically trigger a stress response and cytokine release (e.g., IL-1, TNF), leading to **neutrophilia** (increased neutrophils) rather than neutropenia. * **B. Myeloproliferative Neoplasms (MPN):** As the name suggests, these are clonal disorders (e.g., Polycythemia Vera, CML) characterized by the *overproduction* of one or more formed elements of the blood. They typically present with **leukocytosis** and neutrophilia. * **C. Exercise:** Vigorous physical activity causes **pseudoneutrophilia**. This occurs due to the release of epinephrine, which shifts neutrophils from the "marginal pool" (attached to vessel walls) to the "circulating pool." **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of neutropenia worldwide:** Drug-induced (e.g., chemotherapy, clozapine, carbamazepine, propylthiouracil) [4]. * **Kostmann Syndrome:** A severe congenital neutropenia caused by mutations in the *ELANE* or *HAX1* genes. * **Felty Syndrome Triad:** Rheumatoid arthritis, Splenomegaly, and Neutropenia. * **Aplastic Anemia Hallmark:** Bone marrow biopsy shows "dry tap" and hypocellularity with increased fat spaces [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 662. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 662-663. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 595-596. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 590-592.
Question 437: Which is the most common cause of spherocytosis?
- A. Hereditary spherocytosis
- B. G6PD deficiency
- C. Autoimmune hemolytic anemia (AIHA) (Correct Answer)
- D. Paroxysmal nocturnal hemoglobinuria (PNH)
Explanation: **Explanation:** The presence of spherocytes on a peripheral smear is a hallmark of membrane loss from red blood cells (RBCs). While the name "Hereditary Spherocytosis" (HS) suggests it is the primary cause, **Autoimmune Hemolytic Anemia (AIHA)** is statistically the **most common cause** of spherocytosis overall. **Why AIHA is the correct answer:** In AIHA (specifically the Warm-type), IgG antibodies coat the RBC membrane [1]. As these cells pass through the splenic sinusoids, splenic macrophages "nibble" off portions of the antibody-coated membrane (a process called partial phagocytosis) [1]. The cell loses surface area but maintains its volume, forcing it to assume the most thermodynamically stable shape—a sphere [1]. **Analysis of Incorrect Options:** * **Hereditary Spherocytosis (HS):** This is the most common *inherited* cause of spherocytosis due to defects in membrane proteins (like Ankyrin or Spectrin) [3]. However, acquired causes (AIHA) are more frequent in clinical practice. The blood film in HS typically shows many small, dense spherocytes with loss of central pallor [3]. * **G6PD Deficiency:** This typically presents with **Heinz bodies** and **Bite cells** (degmacytes) due to oxidative stress, rather than prominent spherocytosis [2]. As macrophages pluck out Heinz bodies, some cells may become spherocytes, but the hallmark is the bite cell [2]. * **Paroxysmal Nocturnal Hemoglobinuria (PNH):** This is a stem cell defect involving GPI-anchor proteins. It typically presents with intravascular hemolysis and pancytopenia; spherocytes are not a characteristic feature. **NEET-PG High-Yield Pearls:** * **Differential Diagnosis:** To distinguish HS from AIHA, use the **Direct Coombs Test (DAT)**. AIHA is Coombs positive, while HS is Coombs negative. * **MCHC:** Spherocytosis is the only condition where the Mean Corpuscular Hemoglobin Concentration (MCHC) is characteristically **increased** (>36 g/dL). * **Confirmatory Test for HS:** The Osmotic Fragility Test (increased fragility) or the more specific **EMA Binding test** (Flow cytometry) [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 602-603. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 642-643. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598.
Question 438: Which investigation can distinguish between pregnancy-acquired hemophilia A and lupus anticoagulant?
- A. Factor 8 assay
- B. Dilute Russell's viper venom time (dRVVT) (Correct Answer)
- C. von Willebrand Factor assay
- D. Activated partial thromboplastin time (aPTT)
Explanation: Both pregnancy-acquired hemophilia A (caused by Factor VIII inhibitors) and Lupus Anticoagulant (LA) present with an isolated, prolonged **Activated Partial Thromboplastin Time (aPTT)** that does not correct upon a 1:1 mixing study [1]. Distinguishing between them is critical as one causes life-threatening bleeding while the other is associated with thrombosis. **Why dRVVT is the correct answer:** The **Dilute Russell's Viper Venom Time (dRVVT)** is the gold standard for detecting Lupus Anticoagulants. The venom directly activates Factor X; in the presence of LA (an antiphospholipid antibody), the reaction is inhibited, prolonging the clotting time [3]. This is then confirmed by adding excess phospholipid, which neutralizes the LA and corrects the time. Conversely, dRVVT is **not affected by Factor VIII inhibitors**, as it bypasses the intrinsic pathway where Factor VIII functions. **Analysis of Incorrect Options:** * **Factor 8 Assay:** While Factor VIII levels are low in acquired hemophilia [1], they can also appear falsely low in the presence of a potent Lupus Anticoagulant due to interference with the aPTT-based assay [2]. * **von Willebrand Factor Assay:** This is used to diagnose vWD, which typically presents with a corrected mixing study and does not help differentiate between two types of circulating inhibitors. * **Activated Partial Thromboplastin Time (aPTT):** Both conditions cause a prolonged aPTT that fails to correct on mixing; therefore, it cannot distinguish between them. **Clinical Pearls for NEET-PG:** * **Acquired Hemophilia A:** Post-partum state is a classic trigger [1]. Presents with **bleeding** (ecchymosis, mucosal bleeds). * **Lupus Anticoagulant:** Part of Antiphospholipid Syndrome (APLS). Paradoxically causes **thrombosis** and recurrent pregnancy loss despite a prolonged aPTT [3]. * **Mixing Study Rule:** Correction = Factor deficiency; No correction = Presence of an inhibitor (e.g., LA or FVIII antibody). **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 624-625. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 134-135. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 626-627.
Question 439: In G6PD deficiency, which red blood cells are more prone to hemolysis?
- A. Older red cells (Correct Answer)
- B. Young red cells
- C. Reticulocytes
- D. All are susceptible
Explanation: **Explanation:** **1. Why Older Red Cells are More Prone (The Core Concept):** G6PD (Glucose-6-Phosphate Dehydrogenase) is the rate-limiting enzyme in the Hexose Monophosphate (HMP) shunt, responsible for producing **NADPH**. NADPH is essential for maintaining a pool of reduced glutathione, which protects red blood cells (RBCs) from oxidative stress. In the most common variant (G6PD A-), the enzyme is kinetically stable but has a **shortened half-life**. Because RBCs lack a nucleus and cannot synthesize new proteins, they cannot replace enzymes as they age. Consequently, as RBCs reach the end of their 120-day lifespan, their G6PD levels naturally decline. In deficient individuals, this decline is precipitous; older cells eventually lack enough enzyme to handle oxidative triggers (like fava beans or infections), leading to hemoglobin denaturation (Heinz bodies) and subsequent hemolysis [1]. **2. Why Other Options are Incorrect:** * **Young Red Cells & Reticulocytes:** These cells have been recently synthesized and contain the highest concentration of G6PD. Even in deficient patients, young cells possess enough enzymatic activity to survive oxidative stress. This is why hemolysis in G6PD deficiency is typically **self-limiting**, as the older population is cleared and replaced by resistant younger cells [1]. * **All are Susceptible:** This is incorrect because the susceptibility is strictly age-dependent [1]. **3. NEET-PG High-Yield Pearls:** * **Inheritance:** X-linked recessive (primarily affects males). * **Morphology:** Look for **Heinz bodies** (supravital stain like Crystal Violet) and **Bite cells** (degmacytes) formed by splenic macrophages [1]. * **Diagnostic Pitfall:** Do not test G6PD levels during an acute hemolytic episode. Since older (deficient) cells have lysed, a false-normal result may occur due to the high G6PD levels in the remaining reticulocytes [1]. * **Triggers:** Infections (most common), Drugs (Primaquine, Sulfa drugs, Dapsone), and Fava beans. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 642-643.
Question 440: Hemoglobin electrophoresis is used as a confirmatory test in which of the following anemias?
- A. Iron deficiency anemia
- B. Polycythemia
- C. Hereditary spherocytosis
- D. Sickle cell anemia (Correct Answer)
Explanation: ### Explanation **Correct Option: D. Sickle cell anemia** Hemoglobin electrophoresis is the gold standard confirmatory test for hemoglobinopathies like Sickle cell anemia and Thalassemia. It works on the principle of differential migration of hemoglobin variants in an electric field based on their net molecular charge. In Sickle cell anemia (HbSS), the substitution of glutamic acid (negative charge) by valine (neutral) at the 6th position of the beta-globin chain makes the hemoglobin less negative [1]. Consequently, **HbS moves slower** toward the anode compared to normal HbA. **Why other options are incorrect:** * **A. Iron deficiency anemia:** This is a microcytic hypochromic anemia diagnosed via a **Serum Iron Profile** (low ferritin, low serum iron, high TIBC). Electrophoresis is normal in isolated IDA. * **B. Polycythemia:** This is an increase in red cell mass. Diagnosis involves checking hemoglobin/hematocrit levels, **JAK2 mutation** analysis, and serum erythropoietin levels. * **C. Hereditary spherocytosis:** This is a red cell membrane defect (ankyrin/spectrin deficiency). The confirmatory test is the **Osmotic Fragility Test** or the more specific **EMA Binding test** (flow cytometry). **NEET-PG High-Yield Pearls:** * **Mnemonic for migration (Fastest to Slowest):** **A** Fat **S**anta **C**laus (**A** > **F** > **S** > **C**). HbA moves the fastest toward the anode. * **Alkaline Electrophoresis (pH 8.6):** The initial screening method using cellulose acetate. * **Acid Electrophoresis (pH 6.0):** Used to differentiate HbS from HbD and HbG, which co-migrate on alkaline media. * **Sickling Test:** Uses Sodium metabisulfite; it is a screening test, not a confirmatory one. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 598-599.
Practice by Chapter
Anemias: Classification and Approach
Practice Questions
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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