CLT CLT Hematology & Blood Analysis 2 — Questions and Answers
Question 1: Which anticoagulant is used in the lavender-top (purple) Vacutainer tube for CBC collection?
- Heparin
- Sodium citrate
- EDTA (Correct answer)
- Sodium fluoride
Correct answer: EDTA
EDTA (ethylenediaminetetraacetic acid) is the anticoagulant in lavender-top tubes; it chelates calcium to prevent clotting without altering cell morphology.
Question 2: On a peripheral blood smear, target cells (codocytes) are most associated with which condition?
- Hereditary spherocytosis
- Iron deficiency anemia or liver disease (Correct answer)
- Vitamin B12 deficiency
- Acute lymphoblastic leukemia
Correct answer: Iron deficiency anemia or liver disease
Target cells, which have a bull's-eye appearance, are classically seen in iron deficiency anemia, thalassemia, and liver disease.
Question 3: What does an increased reticulocyte count indicate about bone marrow activity?
- Bone marrow suppression
- Increased red cell production (Correct answer)
- Decreased platelet synthesis
- White cell destruction
Correct answer: Increased red cell production
Reticulocytes are immature red blood cells; an elevated count indicates that the bone marrow is actively producing red cells, often in response to blood loss or hemolysis.
Question 4: Which white blood cell is the most abundant in a normal adult differential count?
- Monocytes
- Lymphocytes
- Neutrophils (Correct answer)
- Eosinophils
Correct answer: Neutrophils
Neutrophils make up approximately 50–70% of circulating white blood cells and are the first responders to bacterial infection.
Question 5: A hematocrit of 55% in an adult male most likely suggests which condition?
- Microcytic anemia
- Polycythemia (Correct answer)
- Thrombocytopenia
- Leukopenia
Correct answer: Polycythemia
A hematocrit above 52% in males indicates polycythemia, an abnormally high proportion of red blood cells in the blood.
Question 6: Which test measures the time it takes for a fibrin clot to form and evaluates the extrinsic coagulation pathway?
- Activated Partial Thromboplastin Time (aPTT)
- Prothrombin Time (PT) (Correct answer)
- Bleeding time
- D-dimer assay
Correct answer: Prothrombin Time (PT)
Prothrombin Time (PT) evaluates the extrinsic and common coagulation pathways and is used to monitor warfarin therapy.
CLT CLT Hematology & Blood Analysis 2
Which anticoagulant is used in the lavender-top (purple) Vacutainer tube for CBC collection?