In the slide test for sickling, 2% sodium metabisulphite is added to the blood because it:

Removes oxygen from the red cells

The inclusion that marks a true LE cell, and separates it from a tart cell, is:

A homogeneous, structureless nuclear mass

A nucleus with its chromatin pattern intact

In a Leishman-stained smear, the red cells are bright red and the white cell nuclei are pale and washed out. What is the most likely cause?

Buffer water that is too acidic

Buffer water that is too alkaline

Hematology: blood cells, counts and smears

44 Kerala PSC Lab Technician Gr II practice questions on Hematology: blood cells, counts and smears, part of Pathology. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
In the slide test for sickling, 2% sodium metabisulphite is added to the blood because it:
1. ALyses the red cells
2. BFixes the red cells
3. CPrecipitates hemoglobin S
4. DRemoves oxygen from the red cells
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Answer: D · Removes oxygen from the red cells
Sodium metabisulphite is a reducing agent that uses up the oxygen under a sealed coverslip. Deoxygenated hemoglobin S polymerises into long fibres that distort the cells into sickle and holly-leaf shapes; slides are read for up to 24 hours. The test is positive in both sickle cell trait and disease, so it cannot separate them; hemoglobin electrophoresis or HPLC does. The coverslip is sealed with petroleum jelly so that air cannot re-oxygenate the cells.
- A: The red cells must stay intact to change shape; lysis would destroy the test.
- B: Fixed cells cannot change shape, so a fixative would prevent sickling.
- C: Precipitation of reduced HbS in a phosphate buffer is the solubility test, not the slide test.
Question 2 · Hard
A 45-year-old man has a spleen palpable 12 cm below the costal margin. Hb 10.5 g/dL; WBC 160,000/µL with myelocytes, metamyelocytes and band forms; basophils 6%; blasts 2%; platelets 450,000/µL. The most likely diagnosis is:
1. ALeukemoid reaction
2. BChronic myeloid leukemia
3. CAcute myeloid leukemia
4. DChronic lymphocytic leukemia
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Answer: B · Chronic myeloid leukemia
A very high WBC with the whole range of maturing granulocytes, basophilia and massive splenomegaly is the classic chronic phase picture of CML. Blasts at 2% are far below the 20% needed for acute leukemia. A leukemoid reaction shows toxic granulation and a high LAP score but no basophilia or massive spleen. The diagnosis is confirmed by finding the Philadelphia chromosome or the BCR::ABL1 fusion.
- A: A leukemoid reaction lacks basophilia and massive splenomegaly and has a high LAP score.
- C: Acute myeloid leukemia needs 20% or more blasts, not 2%.
- D: Chronic lymphocytic leukemia shows small mature lymphocytes and smudge cells, not immature granulocytes.
Question 3 · Medium
The inclusion that marks a true LE cell, and separates it from a tart cell, is:
1. AAn intact red cell
2. BA nucleus with its chromatin pattern intact
3. CA homogeneous, structureless nuclear mass
4. DA clump of bacteria
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Answer: C · A homogeneous, structureless nuclear mass
In SLE, antinuclear antibody (anti-DNA-histone) acts on the nuclei of damaged white cells, which swell into a smooth, homogeneous purple mass, the LE body or hematoxylin body. A neutrophil that engulfs this mass and pushes its own nucleus aside is an LE cell. A tart cell is usually a monocyte that has engulfed a whole nucleus still showing its chromatin pattern, and it is not specific for SLE. The LE cell test has largely been replaced by ANA testing but is still taught.
- A: An engulfed red cell is erythrophagocytosis, not an LE cell.
- B: A nucleus that keeps its chromatin pattern is the inclusion of a tart cell.
- D: Ingested bacteria are seen in infection and are unrelated to the LE phenomenon.
Question 4 · Medium
In a Leishman-stained smear, the red cells are bright red and the white cell nuclei are pale and washed out. What is the most likely cause?
1. AA smear made too thick
2. BBuffer water that is too acidic
3. CBuffer water that is too alkaline
4. DStaining left on too long
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Answer: B · Buffer water that is too acidic
The colour balance of a Romanowsky stain depends on pH. Below about pH 6.8 the acid dye eosin binds strongly and the basic azure dyes stain weakly, so red cells look bright red and nuclei pale. Too alkaline a buffer, long staining or a thick smear gives the opposite picture: an overall blue film with grey-blue red cells. Check the buffer pH (6.8) and the quality of the distilled water first.
- A: A thick smear stains dark blue and its cells overlap.
- C: An alkaline buffer makes the whole film too blue, including the red cells.
- D: Prolonged staining makes the film dark and blue, not pale.
Question 5 · Easy
Besides glacial acetic acid, Turk's diluting fluid contains:
1. AMercuric chloride
2. BFormalin
3. CBrilliant cresyl blue
4. DGentian violet
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Answer: D · Gentian violet
Turk's fluid is dilute glacial acetic acid (about 1.5-2%) tinted with gentian violet. The acid lyses the red cells, and the dye stains the white cell nuclei so that they are easy to count in the four corner squares of the Neubauer chamber. Blood is normally diluted 1 in 20 in the WBC pipette. Nucleated red cells are not lysed and are counted as white cells, so the count must be corrected when they are present.
- A: Mercuric chloride is a preservative in Hayem's RBC diluting fluid.
- B: Formalin is used in RBC diluting fluids such as formol citrate to fix the cells.
- C: Brilliant cresyl blue is a supravital stain for reticulocytes.
Question 6 · Medium
A 30-year-old man has fever, bleeding gums and pancytopenia. His smear shows large blasts, some with needle-shaped, reddish-purple rods in the cytoplasm. These blasts are most likely of which lineage?
1. AMegakaryocytic
2. BMyeloid
3. CLymphoid
4. DErythroid
Answer and explanation in LearnFree account
Question 7 · Easy
Schuffner's dots in enlarged red cells point to which malaria parasite?
1. APlasmodium falciparum
2. BBabesia species
3. CPlasmodium malariae
4. DPlasmodium vivax
Answer and explanation in LearnFree account
Question 8 · Hard
Blood from a patient with chronic leukemia is diluted 1 in 200 in Turk's fluid using the RBC pipette. A total of 300 cells are counted in the four large corner squares of a Neubauer chamber. What is the WBC count?
1. A15,000/µL
2. B150,000/µL
3. C1,500/µL
4. D600,000/µL
Answer and explanation in LearnFree account
Question 9 · Easy
All of the following are Romanowsky stains EXCEPT:
1. AZiehl-Neelsen stain
2. BField's stain
3. CLeishman stain
4. DGiemsa stain
Answer and explanation in LearnFree account
Question 10 · Easy
How does EDTA keep a blood sample from clotting?
1. ABy inhibiting glycolysis
2. BBy precipitating calcium
3. CBy activating antithrombin
4. DBy chelating (binding) calcium ions
Answer and explanation in LearnFree account
Question 11 · Easy
Which stain is used on living, unfixed red cells to count reticulocytes?
1. AGiemsa stain
2. BLeishman stain
3. CNew methylene blue
4. DPerls' Prussian blue
Answer and explanation in LearnFree account
Question 12 · Easy
In adults, which site is preferred when bone marrow aspiration and trephine biopsy are both needed?
1. AProximal tibia
2. BBody of a lumbar vertebra
3. CPosterior superior iliac spine
4. DShaft of the femur
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Question 13 · Medium
In a manual RBC count, blood is diluted 1 in 200 and cells in 80 of the smallest squares (total area 0.2 mm², depth 0.1 mm) are counted. The number counted is multiplied by:
1. A50
2. B10,000
3. C2,000
4. D200
Answer and explanation in LearnFree account
Question 14 · Hard
A 6-year-old boy with beta-thalassemia major has a total WBC count of 21,000/µL by the Neubauer chamber. The differential shows 40 nucleated red cells per 100 white cells. The corrected WBC count is:
1. A20,960/µL
2. B12,600/µL
3. C15,000/µL
4. D29,400/µL
Answer and explanation in LearnFree account
Question 15 · Hard
For an absolute eosinophil count, blood is diluted 1 in 20 in Dunger's fluid and both sides of a Neubauer chamber are filled. A total of 45 eosinophils are counted in all 18 large squares (each 1 mm², depth 0.1 mm). What is the absolute eosinophil count?
1. A2,250/µL
2. B1,000/µL
3. C900/µL
4. D500/µL
Answer and explanation in LearnFree account
Question 16 · Easy
Which diluting fluid is commonly used for a manual platelet count in the Neubauer chamber?
1. ATurk's fluid
2. BDunger's fluid
3. CHayem's fluid
4. D1% ammonium oxalate
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Question 17 · Medium
A smear shows many red cells with a dark central spot, a pale ring around it and a dark outer rim. In which condition are these cells most often seen?
1. AAplastic anemia
2. BThalassemia
3. CHereditary spherocytosis
4. DMegaloblastic anemia
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Question 18 · Easy
What is the usual ratio of granulocytic to nucleated red cell precursors in a healthy adult's marrow aspirate?
1. A3:1
2. B1:1
3. C10:1
4. D1:3
Answer and explanation in LearnFree account
Question 19 · Medium
Which cytochemical stain is positive in myeloblasts but negative in lymphoblasts?
1. APeriodic acid-Schiff
2. BMyeloperoxidase
3. CAcid phosphatase
4. DPerls' Prussian blue
Answer and explanation in LearnFree account
Question 20 · Medium
A 68-year-old man has painless enlarged lymph nodes. WBC is 62,000/µL with 85% small, mature-looking lymphocytes, and the smear shows many smudge cells. The most likely diagnosis is:
1. AChronic lymphocytic leukemia
2. BAcute lymphoblastic leukemia
3. CChronic myeloid leukemia
4. DInfectious mononucleosis
Answer and explanation in LearnFree account
Question 21 · Hard
A patient on cancer chemotherapy has a very low white count, so blood is diluted 1 in 10 instead of 1 in 20. A total of 60 cells are counted in the four corner large squares. What is the WBC count?
1. A3,000/µL
2. B15,000/µL
3. C150/µL
4. D1,500/µL
Answer and explanation in LearnFree account
Question 22 · Hard
A healthy 40-year-old woman has a pre-operative analyzer platelet count of 38,000/µL in an EDTA sample. She has no bruising or bleeding. The feathered edge of her smear shows large platelet clumps. What is the best next step?
1. AReport severe thrombocytopenia to the surgeon
2. BRecount on a citrate sample, correcting for dilution
3. CRepeat the count on the same EDTA sample
4. DTransfuse platelets before the operation
Answer and explanation in LearnFree account
Question 23 · Medium
A patient with a high fever has a WBC count of 19,000/µL. The neutrophils show coarse dark granules and pale blue cytoplasmic patches. These changes most strongly suggest:
1. AViral infection
2. BMegaloblastic anemia
3. CAllergic reaction
4. DSevere bacterial infection
Answer and explanation in LearnFree account
Question 24 · Easy
What is the normal platelet count in a healthy adult?
1. A1.5-4.5 lakh/µL
2. B4,000-11,000/µL
3. C50,000-1 lakh/µL
4. D5-10 lakh/µL
Answer and explanation in LearnFree account
Question 25 · Hard
A 20-year-old student has fever, sore throat and enlarged neck nodes. WBC 14,000/µL with 65% lymphocytes, many of them large with abundant blue cytoplasm indented by neighbouring red cells. Which test should be done next?
1. ASickling test
2. BLeukocyte alkaline phosphatase score
3. CHeterophile antibody (Paul-Bunnell) test
4. DBone marrow aspiration
Answer and explanation in LearnFree account

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Hematology: blood cells, counts and smears

In the slide test for sickling, 2% sodium metabisulphite is added to the blood because it:

A 45-year-old man has a spleen palpable 12 cm below the costal margin. Hb 10.5 g/dL; WBC 160,000/µL with myelocytes, metamyelocytes and band forms; basophils 6%; blasts 2%; platelets 450,000/µL. The most likely diagnosis is:

The inclusion that marks a true LE cell, and separates it from a tart cell, is:

In a Leishman-stained smear, the red cells are bright red and the white cell nuclei are pale and washed out. What is the most likely cause?

Besides glacial acetic acid, Turk's diluting fluid contains:

A 30-year-old man has fever, bleeding gums and pancytopenia. His smear shows large blasts, some with needle-shaped, reddish-purple rods in the cytoplasm. These blasts are most likely of which lineage?

Schuffner's dots in enlarged red cells point to which malaria parasite?

Blood from a patient with chronic leukemia is diluted 1 in 200 in Turk's fluid using the RBC pipette. A total of 300 cells are counted in the four large corner squares of a Neubauer chamber. What is the WBC count?

All of the following are Romanowsky stains EXCEPT:

How does EDTA keep a blood sample from clotting?

Which stain is used on living, unfixed red cells to count reticulocytes?

In adults, which site is preferred when bone marrow aspiration and trephine biopsy are both needed?

In a manual RBC count, blood is diluted 1 in 200 and cells in 80 of the smallest squares (total area 0.2 mm², depth 0.1 mm) are counted. The number counted is multiplied by:

A 6-year-old boy with beta-thalassemia major has a total WBC count of 21,000/µL by the Neubauer chamber. The differential shows 40 nucleated red cells per 100 white cells. The corrected WBC count is:

For an absolute eosinophil count, blood is diluted 1 in 20 in Dunger's fluid and both sides of a Neubauer chamber are filled. A total of 45 eosinophils are counted in all 18 large squares (each 1 mm², depth 0.1 mm). What is the absolute eosinophil count?

Which diluting fluid is commonly used for a manual platelet count in the Neubauer chamber?

A smear shows many red cells with a dark central spot, a pale ring around it and a dark outer rim. In which condition are these cells most often seen?

What is the usual ratio of granulocytic to nucleated red cell precursors in a healthy adult's marrow aspirate?

Which cytochemical stain is positive in myeloblasts but negative in lymphoblasts?

A 68-year-old man has painless enlarged lymph nodes. WBC is 62,000/µL with 85% small, mature-looking lymphocytes, and the smear shows many smudge cells. The most likely diagnosis is:

A patient on cancer chemotherapy has a very low white count, so blood is diluted 1 in 10 instead of 1 in 20. A total of 60 cells are counted in the four corner large squares. What is the WBC count?

A healthy 40-year-old woman has a pre-operative analyzer platelet count of 38,000/µL in an EDTA sample. She has no bruising or bleeding. The feathered edge of her smear shows large platelet clumps. What is the best next step?

A patient with a high fever has a WBC count of 19,000/µL. The neutrophils show coarse dark granules and pale blue cytoplasmic patches. These changes most strongly suggest:

What is the normal platelet count in a healthy adult?

A 20-year-old student has fever, sore throat and enlarged neck nodes. WBC 14,000/µL with 65% lymphocytes, many of them large with abundant blue cytoplasm indented by neighbouring red cells. Which test should be done next?