Hematology (75 Questions)
Red Blood Cell Disorders (25 Questions)
1. A patient presents with microcytic, hypochromic anemia. Laboratory results show: Hgb 8.2 g/dL, MCV 68 fL, ferritin 8 ng/mL, TIBC 450 μg/dL. What is the most likely diagnosis? a) Anemia of chronic disease b) Iron deficiency anemia c) Thalassemia minor d) Sideroblastic anemia
Answer: b) Iron deficiency anemia
Explanation: The combination of microcytic hypochromic anemia with low ferritin and elevated TIBC is characteristic of iron deficiency anemia. Anemia of chronic disease would show normal or elevated ferritin with low TIBC.
2. Which laboratory finding is most characteristic of megaloblastic anemia? a) Microcytes and target cells b) Oval macrocytes and hypersegmented neutrophils c) Sickle cells and target cells d) Spherocytes and polychromasia
Answer: b) Oval macrocytes and hypersegmented neutrophils
Explanation: Megaloblastic anemia (B12 or folate deficiency) characteristically shows oval macrocytes and hypersegmented neutrophils (>5 nuclear lobes). The MCV is typically >100 fL.
3. A peripheral blood smear shows sickle cells, target cells, and Howell-Jolly bodies. Hemoglobin electrophoresis reveals HbS 85%, HbF 10%, HbA2 5%. What is the diagnosis? a) Sickle cell trait b) Sickle cell disease c) Hemoglobin SC disease d) Sickle-beta thalassemia
Answer: b) Sickle cell disease
Explanation: The predominance of HbS (85%) with absence of HbA confirms sickle cell disease. Howell-Jolly bodies indicate functional asplenia common in sickle cell disease.
4. In hereditary spherocytosis, which test is most diagnostic? a) Osmotic fragility test b) Kleihauer-Betke test c) Hemoglobin electrophoresis d) G6PD assay
Answer: a) Osmotic fragility test
Explanation: Hereditary spherocytosis shows increased osmotic fragility due to membrane defects causing spherical red cells that are more susceptible to hemolysis in hypotonic solutions.
5. A patient with thalassemia minor would most likely show: a) Elevated HbA2 and normal iron studies b) Low HbA2 and iron deficiency c) Elevated HbF and iron overload d) Normal hemoglobin pattern
Answer: a) Elevated HbA2 and normal iron studies
Explanation: Beta thalassemia minor typically shows elevated HbA2 (>3.5%) with microcytic anemia but normal iron studies, distinguishing it from iron deficiency.
6. Which finding distinguishes anemia of chronic disease from iron deficiency anemia? a) Low hemoglobin b) Microcytic red cells c) Normal or elevated ferritin d) Low reticulocyte count
Answer: c) Normal or elevated ferritin
Explanation: Anemia of chronic disease shows normal or elevated ferritin due to impaired iron utilization, while iron deficiency shows low ferritin due to depleted iron stores.
7. G6PD deficiency primarily causes: a) Chronic hemolytic anemia b) Episodic hemolysis with oxidative stress c) Microcytic anemia d) Megaloblastic anemia
Answer: b) Episodic hemolysis with oxidative stress
Explanation: G6PD deficiency causes episodic hemolytic anemia triggered by oxidative stress from drugs, infections, or fava beans, not chronic hemolysis.
8. In paroxysmal nocturnal hemoglobinuria (PNH), which test is diagnostic? a) Osmotic fragility b) Flow cytometry for CD55/CD59 c) Hemoglobin electrophoresis d) Kleihauer-Betke test
Answer: b) Flow cytometry for CD55/CD59
Explanation: PNH is diagnosed by flow cytometry showing absence of CD55 and CD59 surface proteins on red cells due to defective GPI anchor synthesis.
9. A patient shows hemolysis with dark urine following primaquine therapy. This suggests: a) Sickle cell disease b) G6PD deficiency c) Hereditary spherocytosis d) Thalassemia
Answer: b) G6PD deficiency
Explanation: Primaquine is an oxidizing drug that triggers hemolysis in G6PD-deficient patients, causing dark urine from hemoglobinuria.
10. Which red cell inclusion is seen in alpha thalassemia? a) Heinz bodies b) HbH inclusions c) Howell-Jolly bodies d) Pappenheimer bodies
Answer: b) HbH inclusions
Explanation: HbH inclusions are beta chain tetramers that form golf ball-like inclusions in alpha thalassemia when stained with brilliant cresyl blue.
11. Cold agglutinin disease is characterized by: a) IgG antibodies reactive at 37°C b) IgM antibodies reactive at 4°C c) Complement deficiency d) Warm autoantibodies
Answer: b) IgM antibodies reactive at 4°C
Explanation: Cold agglutinin disease involves IgM autoantibodies that react optimally at 4°C and cause agglutination and hemolysis in cold temperatures.
12. Which laboratory finding is consistent with hemolytic anemia? a) Low reticulocyte count b) Elevated haptoglobin c) Elevated indirect bilirubin d) Low LDH
Answer: c) Elevated indirect bilirubin
Explanation: Hemolytic anemia causes elevated indirect bilirubin from increased red cell breakdown, along with low haptoglobin and elevated LDH.
13. A patient with chronic kidney disease shows normocytic anemia with low reticulocyte count. This suggests: a) Iron deficiency b) Erythropoietin deficiency c) B12 deficiency d) Hemolysis
Answer: b) Erythropoietin deficiency
Explanation: Chronic kidney disease causes anemia primarily due to decreased erythropoietin production, resulting in normocytic anemia with low reticulocyte count.
14. In microangiopathic hemolytic anemia, the characteristic red cell morphology shows: a) Spherocytes b) Schistocytes c) Target cells d) Stomatocytes
Answer: b) Schistocytes
Explanation: Microangiopathic hemolytic anemia is characterized by schistocytes (fragmented red cells) caused by mechanical trauma in abnormal microvasculature.
15. Lead poisoning causes anemia with which characteristic finding? a) Basophilic stippling b) Howell-Jolly bodies c) Heinz bodies d) Cabot rings
Answer: a) Basophilic stippling
Explanation: Lead poisoning interferes with heme synthesis and causes basophilic stippling of red cells due to ribosomal RNA precipitation.
16. A newborn shows severe anemia with hydrops fetalis. Hemoglobin electrophoresis shows 90% Hb Bart's. This indicates: a) Alpha thalassemia major b) Beta thalassemia major c) Sickle cell disease d) Hereditary persistence of HbF
Answer: a) Alpha thalassemia major
Explanation: Hb Bart's (gamma4) in a newborn with hydrops indicates alpha thalassemia major (absence of all alpha globin genes), which is usually fatal.
17. Which test distinguishes iron deficiency from thalassemia minor? a) Complete blood count b) Hemoglobin electrophoresis c) Mentzer index d) Reticulocyte count
Answer: b) Hemoglobin electrophoresis
Explanation: Hemoglobin electrophoresis shows elevated HbA2 in beta thalassemia minor but is normal in iron deficiency, helping distinguish these microcytic anemias.
18. Aplastic anemia is characterized by: a) Hypercellular bone marrow b) Pancytopenia with hypocellular marrow c) Megaloblastic changes d) Increased reticulocytes
Answer: b) Pancytopenia with hypocellular marrow
Explanation: Aplastic anemia shows pancytopenia (low RBC, WBC, and platelets) due to bone marrow failure with hypocellular marrow on biopsy.
19. In polycythemia vera, which laboratory finding is expected? a) Low erythropoietin level b) High erythropoietin level c) Low oxygen saturation d) High 2,3-DPG
Answer: a) Low erythropoietin level
Explanation: Polycythemia vera is a primary disorder with autonomous red cell production, resulting in suppressed erythropoietin levels due to negative feedback.
20. Which morphologic finding is pathognomonic for malaria? a) Schistocytes b) Parasites within red cells c) Spherocytes d) Target cells
Answer: b) Parasites within red cells
Explanation: Visualization of malaria parasites within red blood cells on peripheral smear is pathognomonic for malaria infection.
21. A patient with chronic lymphocytic leukemia develops anemia with spherocytes and positive direct Coombs test. This indicates: a) Iron deficiency b) Autoimmune hemolytic anemia c) Microangiopathic hemolysis d) Hereditary spherocytosis
Answer: b) Autoimmune hemolytic anemia
Explanation: CLL patients can develop autoimmune hemolytic anemia with positive direct Coombs test and spherocytes from antibody-mediated red cell destruction.
22. Methemoglobinemia causes: a) Microcytic anemia b) Cyanosis with normal oxygen...
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