Platelet Flashcards

*Question: What is the correct term used when platelets are counted manually?

A) Platelet Count

B) Platelet Estimation

C) Platelet Estimate

D) Platelet Enumeration

*Answer: C) Platelet Estimate

*Question: Platelets are best described as:

A) True cells derived from bone marrow

B) Cytoplasmic fragments of megakaryocytes

C) Nuclear fragments of erythrocytes

D) Granular cells from the lymphoid lineage

*Answer: B) Cytoplasmic fragments of megakaryocytes

*Question: Which anticoagulant is most commonly used for platelet estimation?

A) Sodium Citrate

B) Heparin

C) EDTA

D) Sodium Fluoride

*Answer: C) EDTA

*Question: Which anticoagulant is preferred when ONLY platelets are being monitored?

A) EDTA

B) Heparin

C) Sodium Fluoride

D) Sodium Citrate

*Answer: D) Sodium Citrate

*Question: What objective lens is used when performing a platelet estimate?

A) 10× low power objective

B) 40× high dry objective

C) 100× oil immersion objective

D) 4× scanning objective

*Answer: C) 100× oil immersion objective

*Question: How many oil immersion fields are counted during a platelet estimate?

A) 5

B) 8

C) 10

D) 15

*Answer: C) 10

*Question: What is the standard platelet estimate formula?

A) A × 10,000

B) A × 15,000

C) A × 25,000

D) A × 20,000

*Answer: D) A × 20,000

*Question: In the platelet estimate formula, what does "A" represent?

A) Total platelets counted in all fields

B) Average number of platelets per OIO field

C) Absolute platelet count from the analyzer

D) Average RBC count per field

*Answer: B) Average number of platelets per OIO field

*Question: What is the normal platelet range?

A) 100-300 ×10⁹/L

B) 150-400 ×10⁹/L

C) 150-450 ×10⁹/L

D) 200-500 ×10⁹/L

*Answer: C) 150-450 ×10⁹/L

*Question: What is the normal number of platelets per oil immersion field?

A) 2-7

B) 8-20

C) 20-30

D) 5-10

*Answer: B) 8-20

*Question: Reading a thick area of the blood smear will result in:

A) Falsely decreased platelet estimate

B) Accurate platelet estimate

C) Falsely increased platelet estimate

D) No effect on the platelet estimate

*Answer: C) Falsely increased platelet estimate

*Question: Reading a thin area of the blood smear will result in:

A) Falsely increased platelet estimate

B) Accurate platelet estimate

C) No change in the result

D) Falsely decreased platelet estimate

*Answer: D) Falsely decreased platelet estimate

*Question: Which of the following best describes the optimal area for platelet estimation?

A) Cells are overlapping and thick

B) Cells are evenly distributed, non-overlapping, with visible RBC central pallor

C) Cells are too spread apart with no central pallor

D) Area closest to the feathered edge of the smear

*Answer: B) Cells are evenly distributed, non-overlapping, with visible RBC central pallor

*Question: Why does platelet clumping cause a falsely LOW result in automated analyzers?

A) Clumped platelets are counted twice

B) Clumped platelets are too small to detect

C) Clumped platelets appear too large to be recognized as platelets

D) Clumped platelets lyse during analysis

*Answer: C) Clumped platelets appear too large to be recognized as platelets

*Question: Which stain is used in preparing the peripheral blood smear for platelet estimation?

A) Gram stain

B) Giemsa stain

C) Wright stain

D) Ziehl-Neelsen stain

*Answer: C) Wright stain

*Question: Platelet satellitosis is a known pitfall associated with which anticoagulant?

A) Sodium Citrate

B) Heparin

C) Sodium Fluoride

D) EDTA

*Answer: D) EDTA

*Question: Which of the following conditions is associated with THROMBOCYTOPENIA?

A) Post-splenectomy

B) Rheumatic fever

C) Aplastic anemia

D) Acute blood loss

*Answer: C) Aplastic anemia

*Question: Which of the following conditions is associated with THROMBOCYTOSIS?

A) Thrombocytopenic purpura

B) Pernicious anemia

C) Certain acute leukemia

D) Post-splenectomy

*Answer: D) Post-splenectomy

*Question: Petechiae are described as:

A) Large, blanching, red spots measuring 4-10 mm

B) Tiny, non-blanching, purplish-red spots less than 2-4 mm

C) Raised, white spots on the skin

D) Large blisters caused by platelet aggregation

*Answer: B) Tiny, non-blanching, purplish-red spots less than 2-4 mm

*Question: How do purpura differ from petechiae?

A) Purpura are smaller, measuring less than 2 mm

B) Purpura blanch when pressed, petechiae do not

C) Purpura are larger, measuring 4-10 mm

D) Purpura are raised while petechiae are flat

*Answer: C) Purpura are larger, measuring 4-10 mm

*Question: A patient with thrombocytosis is MOST at risk for:

A) Delayed wound healing

B) Excessive bruising

C) Stroke due to platelet clot formation

D) Pernicious anemia

*Answer: C) Stroke due to platelet clot formation

*Question: Which formula is used for platelet estimation in ANEMIC or POLYCYTHEMIC patients?

A) A × 20,000

B) A × 15,000

C) (Avg platelets per field × Total RBC count) ÷ 200 RBCs per field

D) (Total platelets counted × 10) ÷ RBC count

*Answer: C) (Avg platelets per field × Total RBC count) ÷ 200 RBCs per field

*Question: Why is platelet estimation performed even when an automated platelet count is available?

A) Automated counts are always inaccurate

B) To verify analyzer results and serve as internal quality control

C) Manual counting is more precise than automated methods

D) Automated analyzers cannot detect platelets

*Answer: B) To verify analyzer results and serve as internal quality control

*Question: What is the PRIMARY role of platelets in the body?

A) Oxygen transport

B) Immune defense against bacteria

C) Hemostasis — forming the initial platelet plug

D) Production of clotting factors

*Answer: C) Hemostasis — forming the initial platelet plug

*Question: Which of the following is a characteristic feature used to identify platelets on a blood smear?

A) Large size with a bilobed nucleus

B) Small size with granular cytoplasm and no nucleus

C) Pale cytoplasm with a ring-shaped nucleus

D) Dark purple nucleus with abundant cytoplasm

*Answer: B) Small size with granular cytoplasm and no nucleus

*Question: A student counts platelets in 10 OIF and gets a total of 150. What is the platelet estimate?

A) 150 ×10⁹/L

B) 200 ×10⁹/L

C) 300 ×10⁹/L

D) 250 ×10⁹/L

*Answer: C) 300 ×10⁹/L

*Question: Blood film examination of platelets should include assessment of which of the following?

A) Platelet DNA content and nuclear segmentation

B) Diameter, granularity, and overall appearance

C) Platelet enzyme activity and membrane permeability

D) Platelet color under polarized light

*Answer: B) Diameter, granularity, and overall appearance

*Question: Without an anticoagulant, platelets tend to:

A) Lyse immediately

B) Disintegrate into debris

C) Clump together

D) Attach to RBCs

*Answer: C) Clump together

*Question: Which of the following BEST explains why platelet estimation is prone to underestimation?

A) Platelets are counted in too many fields

B) Platelets disintegrate easily and can be mistaken for debris

C) The 100× objective magnifies platelets too much

D) Wright stain causes platelets to become invisible

*Answer: B) Platelets disintegrate easily and can be mistaken for debris

*Question: Platelet estimation by peripheral blood smear is MOST useful in evaluating which of the following?

A) WBC differential and morphology

B) RBC indices and hemoglobin content

C) Thrombocytopenia, thrombocytosis, platelet clumping, and abnormal morphology

D) Coagulation factor deficiencies

*Answer: C) Thrombocytopenia, thrombocytosis, platelet clumping, and abnormal morphology