Free Medical Laboratory Technician Hematology and Coagulation Questions and Answers — Questions and Answers
Question 1: A peripheral blood smear from a patient with multiple myeloma is examined. Which of the following is the most characteristic red blood cell morphology seen in this condition?
- Sickle cells
- Schistocytes
- Rouleaux formation (Correct answer)
- Spherocytes
Correct answer: Rouleaux formation
Rouleaux formation, which appears as stacks of coins, is a classic finding in multiple myeloma. [19, 20] This is caused by increased plasma proteins, specifically immunoglobulins, which reduce the negative charge on the surface of red blood cells, allowing them to aggregate. [6, 20] Sickle cells are characteristic of sickle cell anemia, schistocytes indicate microangiopathic hemolytic anemia, and spherocytes are seen in hereditary spherocytosis and some autoimmune hemolytic anemias.
Question 2: A patient's prothrombin time (PT) is significantly prolonged, while the activated partial thromboplastin time (aPTT) is normal. A deficiency in which of the following coagulation factors would most likely explain these results?
- Factor VIII
- Factor VII (Correct answer)
- Factor IX
- Factor XI
Correct answer: Factor VII
The prothrombin time (PT) evaluates the extrinsic and common pathways of the coagulation cascade. Factor VII is unique to the extrinsic pathway. Therefore, an isolated prolongation of the PT points to a deficiency in Factor VII. [8] Factors VIII, IX, and XI are part of the intrinsic pathway, and deficiencies in these factors would prolong the aPTT.
Question 3: Upon microscopic examination of a bone marrow aspirate from a patient with a suspected hematologic malignancy, the technician notes the presence of needle-like, reddish-pink cytoplasmic inclusions within blast cells. What are these structures called?
- Howell-Jolly bodies
- Pappenheimer bodies
- Heinz bodies
- Auer rods (Correct answer)
Correct answer: Auer rods
Auer rods are crystalline cytoplasmic inclusion bodies composed of fused lysosomes, which are pathognomonic for acute myeloid leukemia (AML) and other myeloid neoplasms. [2, 4, 7] Howell-Jolly bodies are nuclear remnants in red blood cells. [22, 28] Pappenheimer bodies are iron granules in red blood cells. [22, 30] Heinz bodies are denatured hemoglobin, also found in red blood cells.
Question 4: A patient is prescribed daily low-dose aspirin for the prevention of cardiovascular events. Aspirin impairs hemostasis by inhibiting the function of which of the following?
- Fibrinogen
- Thrombin
- Platelets (Correct answer)
- Vitamin K-dependent factors
Correct answer: Platelets
Aspirin works by irreversibly inhibiting the cyclooxygenase-1 (COX-1) enzyme within platelets. [12] This action blocks the production of thromboxane A2, a potent platelet agonist, thereby reducing platelet aggregation and the formation of a platelet plug. [12] This effect lasts for the entire lifespan of the platelet.
Question 5: Which of the following describes the primary role of von Willebrand factor (vWF) in hemostasis?
- Converting prothrombin to thrombin
- Mediating platelet adhesion to exposed collagen (Correct answer)
- Stabilizing the fibrin clot through cross-linking
- Activating the intrinsic coagulation pathway
Correct answer: Mediating platelet adhesion to exposed collagen
Von Willebrand factor (vWF) plays a critical role in primary hemostasis by acting as a bridge between platelets and the site of vascular injury. [1, 9] It binds to exposed collagen in the subendothelium and then tethers platelets via their GpIb receptor, facilitating platelet adhesion and the formation of a primary platelet plug. [3, 9] It also serves as a carrier protein for Factor VIII. [3, 9]
Question 6: A medical laboratory technician is performing a differential on a Wright-stained peripheral blood smear. They identify red blood cell inclusions that are small, irregular, basophilic granules clustered near the periphery of the cell. A Prussian blue stain confirms the presence of iron. What are these inclusions?
- Howell-Jolly bodies
- Basophilic stippling
- Pappenheimer bodies (Correct answer)
- Cabot rings
Correct answer: Pappenheimer bodies
Pappenheimer bodies are abnormal granules of iron, visible as basophilic inclusions on a Wright stain. [22, 30] Their presence is confirmed with a special iron stain like Prussian blue. [24] Howell-Jolly bodies are DNA remnants and are typically single, round, and dense. [24, 28] Basophilic stippling consists of precipitated ribosomes and appears as fine or coarse granules distributed throughout the cell. Cabot rings are rare, thread-like inclusions thought to be remnants of the mitotic spindle.
Free Medical Laboratory Technician Hematology and Coagulation Questions and Answers
A peripheral blood smear from a patient with multiple myeloma is examined.
Which of the following is the most characteristic red blood cell morphology seen in this condition?