Welcome to Part 37 of our Free ASCP MLS Exam Practice Questions series. This section focuses on Red Blood Cell (RBC) Disorders, including the wide range of anemias and hemolytic conditions that clinical laboratory professionals encounter.
RBC disorders are among the most frequently tested areas in the ASCP MLS exam because of their clinical importance and strong laboratory correlation.
🔹 Topics Covered in This Part
- Laboratory findings in RBC disorders (CBC, morphology, special tests)
- Classification of anemias (morphological and pathophysiological)
- Iron deficiency anemia and anemia of chronic disease
- Megaloblastic anemia (Vitamin B12 and folate deficiency)
- Hemolytic anemias (immune, non-immune, hereditary causes)
- Sickle cell disease and thalassemia syndromes
60 MCQs (3161- 3220):
📘 How to Use These Practice Questions
- Questions in this section emphasize the pathophysiology, clinical features, and diagnostic tests for RBC disorders.
- The sequence continues from the previous article — starting at Question 290.
- Answer keys with explanations will follow at the end of the question set for effective review.
- Which of the following is the most common cause of iron deficiency anemia worldwide?
a) Chronic kidney disease
b) Dietary deficiency
c) Chronic blood loss
d) Vitamin B12 deficiency - Which laboratory finding is most consistent with iron deficiency anemia?
a) High serum ferritin
b) Low serum iron and low ferritin
c) Increased MCV
d) Elevated reticulocyte count - A patient with macrocytic anemia, hypersegmented neutrophils, and glossitis most likely has:
a) Iron deficiency anemia
b) Megaloblastic anemia
c) Thalassemia minor
d) Anemia of chronic disease - Pernicious anemia results from deficiency of:
a) Folic acid
b) Vitamin C
c) Vitamin B12 due to intrinsic factor deficiency
d) Vitamin D - Which RBC index is most helpful in distinguishing microcytic anemia?
a) MCV
b) MCHC
c) RDW
d) Reticulocyte count - Which condition shows increased HbA2 and HbF levels on hemoglobin electrophoresis?
a) Sickle cell trait
b) Iron deficiency anemia
c) Beta-thalassemia minor
d) Alpha-thalassemia trait - The presence of Heinz bodies in RBCs is most commonly associated with:
a) G6PD deficiency
b) Iron deficiency anemia
c) Aplastic anemia
d) Sickle cell anemia - In sickle cell anemia, the abnormal hemoglobin present is:
a) HbC
b) HbS
c) HbA2
d) HbE - Which of the following conditions is characterized by normocytic, normochromic anemia with low reticulocyte count?
a) Aplastic anemia
b) Iron deficiency anemia
c) Megaloblastic anemia
d) Thalassemia major - The Schilling test was historically used to diagnose:
a) Iron deficiency anemia
b) Pernicious anemia
c) Hemolytic anemia
d) Thalassemia - Spherocytes are most typically seen in:
a) Hereditary spherocytosis
b) Iron deficiency anemia
c) Megaloblastic anemia
d) Beta-thalassemia trait - Which test best measures RBC destruction in hemolytic anemia?
a) Serum ferritin
b) Reticulocyte count
c) Haptoglobin level
d) Serum folate - Paroxysmal nocturnal hemoglobinuria is caused by:
a) Vitamin B12 deficiency
b) Stem cell mutation causing complement sensitivity
c) Iron deficiency
d) Malaria infection - The main cause of anemia in chronic kidney disease is:
a) Iron malabsorption
b) Decreased erythropoietin production
c) Folate deficiency
d) Hemolysis - Which of the following stains is used to detect Heinz bodies?
a) Wright stain
b) Prussian blue stain
c) Supravital stain
d) PAS stain - A hallmark finding in iron deficiency anemia is:
a) Microcytic, hypochromic RBCs
b) Macrocytic, hyperchromic RBCs
c) Sickle-shaped RBCsd) Bite cells - Which type of anemia is commonly associated with autoimmune gastritis?
a) Sideroblastic anemia
b) Aplastic anemia
c) Pernicious anemia
d) Hemolytic anemia - Which RBC abnormality is characteristic of glucose-6-phosphate dehydrogenase deficiency?
a) Target cells
b) Bite cells
c) Spherocytes
d) Howell–Jolly bodies - Anemia of chronic disease typically shows:
a) High serum iron, high TIBC
b) Low serum iron, low TIBC
c) High MCV
d) Increased HbF - Which condition shows basophilic stippling in RBCs?
a) Iron deficiency anemia
b) Lead poisoning
c) Pernicious anemia
d) Hemolytic anemia - Which of the following is the best initial screening test for thalassemia?
a) Hemoglobin electrophoresis
b) Serum ferritin
c) Reticulocyte count
d) Coombs test - Aplastic anemia is most often associated with:
a) Increased bone marrow cellularity
b) Decreased bone marrow cellularity
c) Increased reticulocytes
d) Increased serum iron - What is the genetic mutation in sickle cell anemia?
a) Valine replaces glutamic acid at position 6 of beta chain
b) Lysine replaces glutamic acid at position 6 of beta chain
c) Deletion of alpha globin gene
d) Insertion mutation in beta globin gene - Which anemia is characterized by ring sideroblasts in the bone marrow?
a) Iron deficiency anemia
b) Sideroblastic anemia
c) Aplastic anemia
d) Pernicious anemia - The osmotic fragility test is used to diagnose:
a) Sickle cell anemia
b) G6PD deficiency
c) Hereditary spherocytosis
d) Thalassemia - A patient with chronic hemolytic anemia is at risk for developing:
a) Kidney stones
b) Gallstones
c) Peptic ulcers
d) Lung fibrosis - What is the characteristic RBC finding in beta-thalassemia major?
a) Macrocytosis
b) Target cells and microcytosis
c) Howell–Jolly bodies
d) Spherocytes - Which laboratory marker is elevated in hemolytic anemia?
a) Haptoglobin
b) LDH
c) Serum folate
d) Serum ferritin - Reticulocytosis is most often seen in which condition?
a) Aplastic anemia
b) Hemolytic anemia
c) Megaloblastic anemia
d) Iron deficiency anemia - Which RBC inclusion is typically found in megaloblastic anemia?
a) Howell–Jolly bodies
b) Heinz bodies
c) Basophilic stippling
d) Pappenheimer bodies - . What is the characteristic erythrocyte found in pernicious anemia?
a) Microcytic
b) Spherocytic
c) Hypochromic
d) Macrocytic - Hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) is primarily caused by:
a) Temperature-dependent antibodies
b) A red cell membrane defect
c) Antibody-mediated complement activation
d) A complement-independent mechanism - Which of the following is most closely associated with idiopathic hemochromatosis?
a) Target cells
b) Iron overload in tissue
c) Cabot rings
d) Ringed sideroblasts - A patient with polycythemia vera treated by phlebotomy is most likely to develop a deficiency of:
a) Vitamin B12
b) Folic acid
c) Iron
d) Erythropoietin - The direct antiglobulin test (DAT) is most useful in distinguishing:
a) Intravascular from extravascular hemolysis
b) Heterozygous from homozygous thalassemia
c) Inherited from acquired spherocytosis
d) Sickle cell trait from sickle cell disease - The anemia of chronic inflammation is characterized by:
a) Decreased iron stores in the reticuloendothelial system
b) Increased serum iron binding capacity (TIBC)
c) Decreased serum iron levels
d) Macrocytic erythrocytes - Which of the following sets of laboratory findings is consistent with hemolytic anemia?
a) Decreased bilirubin; normal reticulocyte count
b) Decreased serum lactate dehydrogenase (LD); normal catabolism of heme
c) Increased serum lactate dehydrogenase (LD); increased catabolism of heme
d) Increased concentration of haptoglobin; marked hemoglobinuria - Deficiency of this enzyme is associated with a hemolytic anemia after exposure to certain drugs and is characterized by red cell inclusions formed by denatured hemoglobin:
a) Pyruvate kinase
b) Lactate dehydrogenase
c) Hexokinase
d) G6PD - Which of the following is the most characteristic finding in autoimmune hemolytic anemia?
a) Increased reticulocyte count
b) Leukopenia and thrombocytopenia
c) Peripheral spherocytosis
d) Positive direct antiglobulin test (DAT) - Peripheral blood smears from patients with untreated pernicious anemia are characterized by:
a) Pancytopenia and macrocytosis
b) Leukocytosis and elliptocytosis
c) Leukocytosis and ovalocytosis
d) Pancytopenia and microcytosis - Laboratory tests performed on a patient indicate macrocytosis and pancytopenia. Which disorder is most likely?
a) Iron deficiency
b) Anemia of chronic inflammation
c) Vitamin B12 deficiency
d) Acute hemorrhage - The characteristic morphologic feature in folic acid deficiency is:
a) Target cells
b) Macrocytosis
c) Basophilic stippling
d) Rouleaux formation - Megaloblastic asynchronous development in the bone marrow indicates:
a) Proliferation of erythrocyte precursors
b) Impaired synthesis of DNA
c) Inadequate production of erythropoietin
d) A deficiency of G6PD - Which of the following are commonly found in association with megaloblastic anemia?
a) Neutropenia and thrombocytopenia
b) Decreased LD activity
c) Increased erythrocyte folate levels
d) Decreased plasma bilirubin levels - A characteristic morphologic feature in hemoglobin C disease is:
a) Macrocytosis
b) Spherocytosis
c) Rouleaux formation
d) Target cells - Thalassemias are characterized by a:
a) Structural abnormality in the hemoglobin molecule
b) Absence of iron in hemoglobin
c) Decreased rate of heme synthesis
d) Decreased rate of globin synthesis - Laboratory findings in hereditary spherocytosis include:
a) Decreased WBC count
b) A positive direct antiglobulin test (DAT)
c) Reticulocytopenia
d) Decreased RBC band 3 protein - The characteristic morphologic feature in lead poisoning is:
a) Macrocytosis
b) Target cells (codocytes)
c) Basophilic stippling
d) Rouleaux formation - Which parameter is most consistently abnormal in cases of hereditary spherocytosis?
a) RBC count
b) MCV
c) Hemoglobin
d) MCHC - The basic mechanism associated with the development of sideroblastic anemia is:
a) A quantitative decrease in the production of globin chains
b) An enzymatic defect in heme synthesis causing iron accumulation
c) Defective iron utilization
d) Ineffective erythropoietin production decreasing RBC response - Which of the following tumors is associated with erythrocytosis due to excessive erythropoietin production?
a) Sarcoma
b) Renal cell carcinoma
c) Basal cell carcinoma
d) Squamous cell carcinoma of the lung - Which abnormal RBC morphology is typically present on a Wright-Giemsa stained smear during a hemolytic episode in G6PD deficiency?
a) Cabot rings
b) Microcytosis
c) Bite cells
d) Heinz bodies - Which of the following hemoglobinopathies is associated with the formation of rod-shaped crystals within red blood cells?
a) HbS
b) HbC
c) HbSC
d) HbD - Hemoglobin H disease results from the absence of:
a) 1 of 4 alpha-globin genes
b) 2 of 4 alpha-globin genes
c) 3 of 4 alpha-globin genes
d) All 4 alpha-globin genes - In an uncomplicated case of severe iron deficiency anemia, which pattern of results is typical?
a) Serum Iron: Decreased, TIBC: Decreased, Storage Iron: Decreased
b) Serum Iron: Decreased, TIBC: Increased, Storage Iron: Decreased
c) Serum Iron: Increased, TIBC: Decreased, Storage Iron: Increased
d) Serum Iron: Increased, TIBC: Normal, Storage Iron: Decreased - A patient with a chronic urinary tract infection presents with a microcytic anemia, low serum iron, low TIBC, and normal serum ferritin. This is most consistent with:
a) Iron deficiency anemia
b) Anemia of chronic inflammation
c) Hemochromatosis
d) Acute blood loss - What is the most common cause of anemia in hospitalized patients?
a) Inadequate iron intake
b) Hemolytic anemia
c) Inadequate folate intake
d) Anemia of chronic inflammation - A patient with sickle cell anemia and a baseline hemoglobin of 8 g/dL presents with fever and extreme weakness. Their hemoglobin is now 4 g/dL with a reticulocyte count of 0.1%. The most likely explanation is:
a) Increased hemolysis due to hypersplenism
b) Aplastic crisis
c) Thrombotic crisis
d) Occult blood loss - The Donath-Landsteiner antibody, associated with paroxysmal cold hemoglobinuria, is characterized as a(n):
a) IgM cold agglutinin
b) Biphasic IgM hemolysin
c) IgG biphasic hemolysin
d) IgG warm agglutinin - Which of the following conditions may contribute to lethargy, abdominal pain, and hemoglobinuria in some patients with a G6PD deficiency?
a) Dehydration
b) Excess iron
c) Ingesting fava beans
d) Increased glucose
📌 How to Use This Practice Set
- Answer each question before checking the key.
- Focus on why the correct answer is right and the others are wrong.
- Use this set as timed practice to simulate the real exam environment.
Answer Key
Answer Key:
- c) Chronic blood loss
- b) Low serum iron and low ferritin
- b) Megaloblastic anemia
- c) Vitamin B12 due to intrinsic factor deficiency
- a) MCV
- c) Beta-thalassemia minor
- a) G6PD deficiency
- b) HbS
- a) Aplastic anemia
- b) Pernicious anemia
- a) Hereditary spherocytosis
- c) Haptoglobin level
- b) Stem cell mutation causing complement sensitivity
- b) Decreased erythropoietin production
- c) Supravital stain
- a) Microcytic, hypochromic RBCs
- c) Pernicious anemia
- b) Bite cells
- b) Low serum iron, low TIBC
- b) Lead poisoning
- a) Hemoglobin electrophoresis
- b) Decreased bone marrow cellularity
- a) Valine replaces glutamic acid at position 6 of beta chain
- b) Sideroblastic anemia
- c) Hereditary spherocytosis
- b) Gallstones
- b) Target cells and microcytosis
- b) LDH
- b) Hemolytic anemia
- a) Howell–Jolly bodies
- d) Macrocytic
- b) A red cell membrane defect
- b) Iron overload in tissue
- c) Iron
- c) Inherited from acquired spherocytosis
- c) Decreased serum iron levels
- c) Increased serum lactate dehydrogenase (LD); increased catabolism of heme
- d) G6PD
- d) Positive direct antiglobulin test (DAT)
- a) Pancytopenia and macrocytosis
- c) Vitamin B12 deficiency
- b) Macrocytosis
- b) Impaired synthesis of DNA
- a) Neutropenia and thrombocytopenia
- d) Target cells
- d) Decreased rate of globin synthesis
- d) Decreased RBC band 3 protein
- c) Basophilic stippling
- d) MCHC
- b) An enzymatic defect in heme synthesis causing iron accumulation
- b) Renal cell carcinoma
- c) Bite cells
- b) HbC
- c) 3 of 4 alpha-globin genes
- b) Serum Iron: Decreased, TIBC: Increased, Storage Iron: Decreased
- b) Anemia of chronic inflammation
- d) Anemia of chronic inflammation
- b) Aplastic crisis
- c) IgG biphasic hemolysin
- c) Ingesting fava beans
Top 8 Medical Laboratory Scientist (MLS) Exams:
Top 8 Medical Laboratory Scientist (MLS) Exams that are recognized globally and can help professionals validate their credentials and enhance their career opportunities:
1. ASCP – American Society for Clinical Pathology (USA)
- Exam Name: MLS(ASCP)
- Eligibility: Bachelor’s degree with clinical laboratory experience.
- Global Recognition: High
- Purpose: Certifies Medical Laboratory Scientists in the United States and internationally.
2. AMT – American Medical Technologists (USA)
- Exam Name: MLT(AMT) or MT(AMT)
- Eligibility: Academic and/or work experience in medical laboratory technology.
- Global Recognition: Moderate
- Purpose: Credentialing for medical technologists and technicians.
3. AIMS – Australian Institute of Medical and Clinical Scientists
- Exam Name: AIMS Certification Exam
- Eligibility: Assessment of qualifications and work experience.
- Recognition: Required for practice in Australia.
- Purpose: Certification and registration in Australia.
4. CSMLS – Canadian Society for Medical Laboratory Science
- Exam Name: CSMLS General or Subject-specific Exams
- Eligibility: Graduation from a CSMLS-accredited program or equivalent.
- Recognition: Canada
- Purpose: Entry-to-practice certification in Canada.
5. IBMS – Institute of Biomedical Science (UK)
- Exam Name: Registration and Specialist Portfolio Assessment
- Eligibility: Accredited degree and lab experience.
- Recognition: UK and some Commonwealth countries.
- Purpose: Biomedical Scientist registration with the HCPC (UK).
6. HAAD / DOH – Department of Health, Abu Dhabi (UAE)
- Exam Name: DOH/HAAD License Exam
- Eligibility: Degree in medical laboratory science and experience.
- Recognition: UAE (Abu Dhabi)
- Purpose: Licensure for medical laboratory practice in Abu Dhabi.
7. DHA – Dubai Health Authority (UAE)
- Exam Name: DHA License Exam for Medical Laboratory Technologists
- Eligibility: Relevant degree and experience.
- Recognition: Dubai, UAE
- Purpose: Professional license for clinical laboratory practice in Dubai.
8. MOH – Ministry of Health (Gulf Countries like UAE, Saudi Arabia, Kuwait)
- Exam Name: MOH License Exam
- Eligibility: BSc/Diploma in Medical Laboratory + experience.
- Recognition: Varies by country.
- Purpose: Required for practicing in public and private sector labs.
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