Hematology Practice Questions

Q: Which of the following is NOT seen in Paroxysmal Nocturnal Hemoglobinuria?

Decreased LDH. **Explanation:** **Paroxysmal Nocturnal Hemoglobinuria (PNH)** is an acquired clonal hematopoietic stem cell disorder caused by a mutation in the **PIGA gene**. This leads to a deficiency of GPI-anchored proteins, specifically **CD55 (DAF)** and **CD59 (MIRL)**, which normally protect red blood cells from complement-mediated lysis [1]. **Why "Decreased LDH" is the correct answer:** PNH is characterized by **intravascular hemolysis** [1]. When red cells rupture within the circulation, lactate dehydrogenase (LDH), an intracellular enzyme, is released into the plasma. Therefore, **elevated LDH** (often >5-10 times the upper limit of normal) is a hallmark of PNH, not decreased LDH. **Analysis of incorrect options:** * **Thrombosis:** This is the most common cause of death in PNH. Hemolysis releases free hemoglobin, which scavenges Nitric Oxide (NO), leading to smooth muscle dystonia and a pro-thrombotic state. Common sites include hepatic veins (Budd-Chiari syndrome) and cerebral sinuses. * **Hemosiderinuria:** Chronic intravascular hemolysis leads to the filtration of hemoglobin by the kidneys. Iron is deposited in the renal tubular cells as hemosiderin, which is then sloughed into the urine. This often leads to iron deficiency. * **Thrombocytopenia:** PNH is a stem cell disorder. It frequently overlaps with **Aplastic Anemia**, and the defective clone can affect all cell lines, leading to pancytopenia (anemia, leucopenia, and thrombocytopenia). **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Diagnosis:** Flow Cytometry (shows absence of CD55 and CD59 on RBCs and WBCs). * **Classic Triad:** Hemolytic anemia, Pancytopenia, and Thrombosis. * **Treatment:** **Eculizumab** (a monoclonal antibody against Complement C5) is the drug of choice. * **Screening Test:** FLAER (Fluorescent Proaerolysin) assay is highly sensitive for detecting the PNH clone.

Q: A patient diagnosed with deep vein thrombosis is being treated with heparin. Which of the following tests will you order to adjust its dosage?

Activated partial thromboplastin time. The correct answer is **Activated partial thromboplastin time (aPTT)**. **1. Why aPTT is correct:** Unfractionated Heparin (UFH) exerts its anticoagulant effect by binding to Antithrombin III, which subsequently inactivates Thrombin (Factor IIa) and Factor Xa [1]. The aPTT measures the integrity of the **intrinsic and common pathways** of the coagulation cascade [2]. Since heparin primarily affects these pathways, the aPTT is the standard laboratory test used to monitor its therapeutic efficacy and adjust dosages to ensure the patient remains within the "therapeutic window" (typically 1.5 to 2.5 times the control value) [3]. **2. Why other options are incorrect:** * **Platelet count:** While heparin can cause Heparin-Induced Thrombocytopenia (HIT), platelet counts are used to monitor for this *complication*, not to adjust the anticoagulant dosage itself. * **Prothrombin time (PT/INR):** This test monitors the **extrinsic pathway** and is the standard for monitoring **Warfarin** therapy, not heparin [3]. * **Bleeding time:** This measures platelet function and vascular integrity; it is not a reliable or specific indicator for heparin's anticoagulant effect. **3. Clinical Pearls for NEET-PG:** * **Low Molecular Weight Heparin (LMWH):** Unlike UFH, LMWH (e.g., Enoxaparin) does not require routine monitoring. If monitoring is necessary (e.g., in renal failure or pregnancy), the **Anti-Factor Xa assay** is used. * **Antidote:** The specific neutralizer for heparin overdose is **Protamine sulfate**. * **Mechanism:** Heparin acts as a catalyst, increasing the activity of Antithrombin III by 1000-fold [1].

Q: A 70-year-old woman, previously in good health, is found to have an asymptomatic monoclonal immunoglobulin peak on serum electrophoresis. Her physical examination is normal, as is her CBC, electrolytes, renal function, and calcium level. A skeletal survey does not reveal any osteolytic lesions, and a bone-marrow aspirate reveals 5% plasma cells. Which of the following is the most likely diagnosis?

monoclonal gammopathy of uncertain significance (MGUS). ### Explanation The patient presents with an incidental finding of a monoclonal (M) protein spike without any associated end-organ damage. This clinical picture is classic for **Monoclonal Gammopathy of Undetermined Significance (MGUS)**. **1. Why MGUS is the Correct Answer:** MGUS is defined by a triad of specific criteria, all of which are met in this case: * **M-protein level:** < 3 g/dL. * **Bone marrow plasma cells:** < 10% (this patient has 5%). * **Absence of CRAB features:** No **C**alcium elevation, **R**enal insufficiency, **A**nemia, or **B**one lesions. Since the patient is asymptomatic with normal labs and a skeletal survey, MGUS is the most likely diagnosis. **2. Why the Other Options are Incorrect:** * **Multiple Myeloma:** Requires ≥10% clonal plasma cells in the bone marrow AND evidence of end-organ damage (CRAB features). This patient has only 5% plasma cells and no CRAB features. * **Waldenstrom Macroglobulinemia:** This is a lymphoplasmacytic lymphoma characterized by an IgM M-spike and bone marrow infiltration by lymphoplasmacytic cells. It typically presents with hyperviscosity symptoms, hepatosplenomegaly, or lymphadenopathy, which are absent here. * **Amyloidosis:** While associated with monoclonal proteins, it presents with systemic symptoms like macroglossia, nephrotic syndrome, restrictive cardiomyopathy, or hepatomegaly. **3. NEET-PG High-Yield Pearls:** * **Risk of Progression:** MGUS progresses to Multiple Myeloma at a rate of approximately **1% per year**. * **Management:** MGUS does not require chemotherapy. The standard of care is **"Watchful Waiting"** with periodic monitoring of serum electrophoresis. * **Smoldering Myeloma:** Defined as M-protein ≥ 3 g/dL OR bone marrow plasma cells 10–60%, but still **without** CRAB features. * **Most Common Type:** IgG is the most common isotype found in MGUS.

Q: Which of the following is NOT true regarding Waldenström's macroglobulinemia?

Hypercalcemia is present.. Waldenström’s Macroglobulinemia (WM) is a **lymphoplasmacytic lymphoma** characterized by the infiltration of the bone marrow by neoplastic cells that secrete a monoclonal **IgM** protein [1]. **Why Option D is the Correct Answer:** Unlike Multiple Myeloma (MM), Waldenström’s Macroglobulinemia is typically **not** associated with lytic bone lesions or significant bone destruction [1]. Consequently, **hypercalcemia and renal failure (due to light chains) are rare** in WM. If a patient presents with high IgM and lytic lesions, the diagnosis is more likely "IgM Myeloma" rather than WM. **Analysis of Incorrect Options:** * **Option A (Lymphadenopathy):** WM is a lymphoma. Unlike Multiple Myeloma, patients frequently present with organomegaly, including **lymphadenopathy and hepatosplenomegaly** (in ~20-40% of cases) [1]. * **Option B (Blood Viscosity):** IgM is a large pentameric molecule. High levels significantly increase serum viscosity, leading to **Hyperviscosity Syndrome** (headache, visual disturbances, and mucosal bleeding) [1]. * **Option C (IgM Increase):** By definition, WM involves a monoclonal gammopathy of the **IgM** class (usually >3 g/dL) [1]. **NEET-PG High-Yield Pearls:** 1. **Genetic Marker:** Over 90% of WM patients possess the **MYD88 L265P mutation**. 2. **Clinical Triad:** Hyperviscosity, lymphadenopathy/splenomegaly, and anemia [1]. 3. **Diagnosis:** Bone marrow biopsy shows **lymphoplasmacytic infiltration** (CD19+, CD20+, CD22+, CD10-, CD5-). 4. **Dutcher Bodies:** Periodic acid–Schiff (PAS)-positive intranuclear inclusions of immunoglobulins are a classic pathological finding. 5. **Treatment:** Plasmapheresis is the immediate treatment for symptomatic hyperviscosity; Rituximab-based regimens are used for definitive therapy [1].

Q: A 23-year-old female presents with a 2-year history of anemia and jaundice. A peripheral smear shows spherocytes. What is the most appropriate investigation to perform?

Coombs test. **Explanation:** The clinical presentation of anemia, jaundice, and spherocytes on a peripheral smear suggests **Spherocytosis**. In clinical practice, the two primary differentials for spherocytes are **Hereditary Spherocytosis (HS)** and **Autoimmune Hemolytic Anemia (AIHA)**. **Why Coombs Test is the correct answer:** The first and most critical step in the diagnostic algorithm for spherocytosis is to differentiate between an inherited membrane defect (HS) and an acquired immune-mediated process (AIHA) [1]. The **Direct Antiglobulin Test (Coombs test)** is the gold standard for this [1]. A positive Coombs test confirms AIHA, while a negative test points toward HS. Since AIHA is a common cause of acquired spherocytosis and requires entirely different management (steroids vs. splenectomy), it must be ruled out first. **Analysis of Incorrect Options:** * **A. Reticulocyte count:** While this will be elevated in any hemolytic anemia, it is non-specific and does not help differentiate the cause of spherocytes. * **B. Osmotic fragility test:** Historically used for HS, this test is now largely replaced by the **EMA Binding test** (Eosin-5-maleimide flow cytometry). Furthermore, osmotic fragility is increased in *both* HS and AIHA, making it less useful than the Coombs test for initial differentiation. * **D. Bone marrow aspiration:** This is generally not indicated in the workup of hemolytic anemias unless a primary bone marrow failure or malignancy is suspected. **NEET-PG High-Yield Pearls:** * **Spherocytes** are smaller, denser RBCs that have lost their central pallor due to loss of surface area [1]. * **Confirmatory test for HS:** EMA Binding test (Most sensitive/specific). * **MCHC:** Characteristically **elevated** (>36 g/dL) in Hereditary Spherocytosis [1]. * **Treatment of choice for HS:** Splenectomy (usually delayed until after age 5-6 to reduce sepsis risk).

Q: During the evaluation of a case of polycythemia, which of the following investigations is LEAST likely to be required to establish the cause?

Serum iron profile. The evaluation of polycythemia focuses on distinguishing between **Primary Polycythemia** (Polycythemia Vera - PV) and **Secondary Polycythemia** (driven by Erythropoietin) [1]. ### Why Serum Iron Profile is the Least Likely Required While iron deficiency can occasionally occur in Polycythemia Vera due to increased red cell production, a **Serum Iron Profile** is not a diagnostic tool to establish the *cause* of polycythemia. In fact, iron deficiency can lead to microcytosis, which might paradoxically mask the rise in hematocrit, but it does not help differentiate between primary and secondary causes. ### Explanation of Other Options * **Erythropoietin (EPO) Level:** This is the initial step in the algorithm. Low EPO levels suggest Polycythemia Vera (Primary), while high levels suggest Secondary Polycythemia (e.g., chronic hypoxia or EPO-secreting tumors). * **Arterial Blood Gas (ABG):** This is crucial to identify **hypoxia-driven secondary polycythemia**. An $SaO_2 < 92\%$ indicates that the polycythemia is a compensatory response to chronic lung disease, cyanotic heart disease, or high altitude [1]. * **Bone Marrow Examination:** In cases where PV is suspected (Low EPO + JAK2 mutation), a bone marrow biopsy is a **WHO major criterion**. It reveals "panmyelosis" (increased cellularity of erythroid, myeloid, and megakaryocytic lines). ### NEET-PG High-Yield Pearls * **WHO Criteria for PV:** Requires 3 Major (High Hb/Hct, BM Panmyelosis, JAK2 mutation) OR 2 Major + 1 Minor (Low Serum EPO). * **JAK2 V617F Mutation:** Present in >95% of PV cases [1]. * **Spurious Polycythemia (Gaisbock Syndrome):** Seen in stressed, hypertensive, obese males due to decreased plasma volume rather than increased red cell mass [1]. * **Rule of Thumb:** If EPO is high, look at the lungs (ABG) or kidneys (Ultrasound for Renal Cell Carcinoma).

Question 1

Which of the following is NOT seen in Paroxysmal Nocturnal Hemoglobinuria?

Accepted Answer

Decreased LDH

Answer

Thrombosis

Answer

Hemosiderinuria

Answer

Thrombocytopenia

Question 2

A 47-year-old man with a history of sickle cell disease has had numerous hospitalizations requiring the placement of intravenous lines. The patient has poor peripheral venous access, and a catheter is placed in the right subclavian vein. The patient subsequently develops right arm discomfort and swelling, and a temperature of 40.1°C with chills. Multiple blood cultures are taken, and gram-positive cocci are isolated. The organism is catalase-positive and grows on mannitol salt agar, but does not turn the agar yellow; the colonies are gamma-hemolytic on a sheep blood agar plate. Which of the following organisms is the most likely cause of this patient's symptoms?

Accepted Answer

Staphylococcus epidermidis

Answer

Enterococcus faecalis

Answer

Staphylococcus aureus

Answer

Streptococcus agalactiae

Question 3

A 57-year-old man, with a history of chronic alcohol ingestion, is admitted to the hospital with acute alcoholic intoxication and lobar pneumonia. Physical examination reveals pallor; a large, tender liver; and consolidation of the right lower lobe. Laboratory data include hemoglobin of 7 g/dL, WBC of 4000/mL, and platelet count of 85,000/mL. Which of the following is the most likely factor for the anemia?

Accepted Answer

Toxic marrow suppression

Answer

Hemolysis

Answer

Hemobilia

Answer

Vitamin B12 deficiency

Question 4

A 45-year-old man complains of recurrent nausea and abdominal distress. A gastric biopsy shows atrophy of the mucosa in the fundus and body, with marked lymphocytic infiltration. Blood studies show severe macrocytic anemia with a mean corpuscular volume of 110 mm3. In addition, numerous hypersegmented neutrophils are appreciated on a blood smear. Which of the following is the MOST likely pathogenetic mechanism of this patient's anemia?

Accepted Answer

Autoantibodies to intrinsic factor

Answer

Chronic blood loss

Answer

Deficient iron absorption

Answer

Helicobacter pylori infection

Question 5

A patient diagnosed with deep vein thrombosis is being treated with heparin. Which of the following tests will you order to adjust its dosage?

Accepted Answer

Activated partial thromboplastin time

Answer

Platelet count

Answer

Prothrombin time

Answer

Bleeding time

Question 6

What is the most serious complication of acute hemolytic anemia in G6PD deficiency?

Accepted Answer

Acute renal failure

Answer

Congestive cardiac failure

Answer

Cerebral infarction

Answer

Acute liver failure

Question 7

A 70-year-old woman, previously in good health, is found to have an asymptomatic monoclonal immunoglobulin peak on serum electrophoresis. Her physical examination is normal, as is her CBC, electrolytes, renal function, and calcium level. A skeletal survey does not reveal any osteolytic lesions, and a bone-marrow aspirate reveals 5% plasma cells. Which of the following is the most likely diagnosis?

Accepted Answer

monoclonal gammopathy of uncertain significance (MGUS)

Answer

multiple myeloma

Answer

Waldenstrom macroglobulinemia

Answer

amyloidosis

Question 8

Which of the following is NOT true regarding Waldenström's macroglobulinemia?

Accepted Answer

Hypercalcemia is present.

Answer

Lymphadenopathy is usually present.

Answer

Blood viscosity is increased.

Answer

IgM immunoglobulin is increased.

Question 9

A 23-year-old female presents with a 2-year history of anemia and jaundice. A peripheral smear shows spherocytes. What is the most appropriate investigation to perform?

Accepted Answer

Coombs test

Answer

Reticulocyte count

Answer

Osmotic fragility test

Answer

Bone marrow aspiration

Question 10

During the evaluation of a case of polycythemia, which of the following investigations is LEAST likely to be required to establish the cause?

Accepted Answer

Serum iron profile

Answer

Erythropoietin level

Answer

Arterial blood gas analysis

Answer

Bone marrow examination

Hematology — MCQs

Hematology — MCQs

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