A 38-year-old woman has confusion and bruising. Results: Hb 74 g/L (7.4 g/dL), platelets 16 × 10^9/L, LD 1,480 U/L (reference 120-250), DAT negative, PT and APTT normal. A technologist reviews 1,000 red cells in the monolayer of the film and records: helmet cells 5, small triangular fragments 3, keratocytes (horn cells) 3, small crescent-shaped fragments 2, echinocytes 28, target cells 11 and teardrop cells 6. The laboratory follows the ICSH recommendation, in which a schistocyte count above 1% in an adult supports a thrombotic microangiopathy. The technologist should report:

Schistocytes 1.3%, supporting a thrombotic microangiopathy

Schistocytes 0.5%, not supporting a thrombotic microangiopathy

Schistocytes 0.8%, not supporting a thrombotic microangiopathy

Schistocytes 5.8%, supporting a thrombotic microangiopathy

A 23-year-old man with suspected aplastic anemia or acute leukemia has WBC 0.6 × 10^9/L, Hb 68 g/L (6.8 g/dL) and platelets 9 × 10^9/L. The analyzer suppresses its differential because too few white cells were counted. After scanning two routine wedge films, the technologist has found only 31 white cells, all looking mature. The hematologist wants to know today whether any blasts are present, because the marrow cannot be done until tomorrow. Which step best allows enough white cells to be classified and a proper search for blasts?

Make films from the buffy coat of a centrifuged sample

Report no differential until the marrow is examined

Make thick films using a larger drop of the EDTA blood

Report a 25-cell differential with each value times four

A 26-year-old man is admitted 3 hours after flame burns to 40% of his body surface. Results: Hb 172 g/L (17.2 g/dL), Hct 0.46 L/L, MCV 81 fL, MCHC 374 g/L (reference 320-360), platelets 242 × 10^9/L, PT, APTT and fibrinogen normal, DAT negative. A CBC a year ago was normal, with an MCV of 89 fL. The film shows many very small, dense, spherical red cells, red cells with small rounded buds at their edges, and occasional fragments. What is the most likely cause of the red cell changes?

Direct heat damage to the red cell membrane

Warm autoimmune hemolytic anemia

Disseminated intravascular coagulation

Hereditary spherocytosis under stress

A 56-year-old man with advanced alcoholic cirrhosis has worsening anemia, a raised indirect bilirubin and a raised reticulocyte count. His film shows many dense, contracted red cells bearing 3 to 10 sharp projections that vary in length and spacing. These cells are best described as:

Acanthocytes from excess membrane cholesterol

Spherocytes from immune membrane damage

Echinocytes from prolonged sample storage

Schistocytes from intravascular fragmentation

A small cell with a round, very dense nucleus could be a small lymphocyte or an orthochromic normoblast. Which feature identifies the normoblast?

Pink-orange cytoplasm like mature red cells

A narrow rim of pale sky-blue cytoplasm

A few azurophilic granules in the cytoplasm

A visible nucleolus in the nucleus

Peripheral smear: preparation, staining and morphology

26 DOH Abu Dhabi (HAAD) lab licensing practice questions on Peripheral smear: preparation, staining and morphology, part of Hematology. 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 · Hard
A 38-year-old woman has confusion and bruising. Results: Hb 74 g/L (7.4 g/dL), platelets 16 × 10^9/L, LD 1,480 U/L (reference 120-250), DAT negative, PT and APTT normal. A technologist reviews 1,000 red cells in the monolayer of the film and records: helmet cells 5, small triangular fragments 3, keratocytes (horn cells) 3, small crescent-shaped fragments 2, echinocytes 28, target cells 11 and teardrop cells 6. The laboratory follows the ICSH recommendation, in which a schistocyte count above 1% in an adult supports a thrombotic microangiopathy. The technologist should report:
1. ASchistocytes 1.3%, supporting a thrombotic microangiopathy
2. BSchistocytes 0.5%, not supporting a thrombotic microangiopathy
3. CSchistocytes 0.8%, not supporting a thrombotic microangiopathy
4. DSchistocytes 5.8%, supporting a thrombotic microangiopathy
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Answer: A · Schistocytes 1.3%, supporting a thrombotic microangiopathy
Under ICSH guidance, schistocytes are red cell fragments: small triangles with sharp angles and straight edges, small crescents, helmet cells and keratocytes. Here 5 + 3 + 3 + 2 = 13 of 1,000 red cells, or 1.3%, which is above the 1% cut-off. Echinocytes, target cells and teardrop cells are not fragments and must not be added in, as the 5.8% figure does. Counting only helmet cells (0.5%), or only helmet cells and triangles (0.8%), under-reports the fragmentation and could delay urgent treatment of suspected TTP. A count suggesting a thrombotic microangiopathy should be communicated to the clinician without delay.
- B: Triangles, crescents and keratocytes count as well as helmet cells.
- C: Keratocytes and small crescents also count as schistocytes.
- D: Echinocytes, target cells and teardrop cells are not schistocytes.
Question 2 · Hard
A 23-year-old man with suspected aplastic anemia or acute leukemia has WBC 0.6 × 10^9/L, Hb 68 g/L (6.8 g/dL) and platelets 9 × 10^9/L. The analyzer suppresses its differential because too few white cells were counted. After scanning two routine wedge films, the technologist has found only 31 white cells, all looking mature. The hematologist wants to know today whether any blasts are present, because the marrow cannot be done until tomorrow. Which step best allows enough white cells to be classified and a proper search for blasts?
1. AReport no differential until the marrow is examined
2. BMake films from the buffy coat of a centrifuged sample
3. CMake thick films using a larger drop of the EDTA blood
4. DReport a 25-cell differential with each value times four
Show answerHide answer
Answer: B · Make films from the buffy coat of a centrifuged sample
When the WBC is below about 1 × 10^9/L, a routine film holds too few white cells for a useful differential, and rare blasts are easily missed. Centrifuging the EDTA blood concentrates the leukocytes in the buffy coat, which is collected with a little plasma, mixed gently and spread as wedge films, so many more cells can be classified on each slide. Thick films distort the cells, so blasts cannot be identified reliably. Scaling up a 25-cell count gives percentages with a very wide error, and waiting for the marrow withholds information the hematologist needs now.
- A: The blood review is needed today, and a buffy coat film makes it possible.
- C: Thick films distort the cells, so blasts cannot be identified reliably.
- D: A 25-cell count is too small; its scaled percentages carry a very large error.
Question 3 · Hard
A 26-year-old man is admitted 3 hours after flame burns to 40% of his body surface. Results: Hb 172 g/L (17.2 g/dL), Hct 0.46 L/L, MCV 81 fL, MCHC 374 g/L (reference 320-360), platelets 242 × 10^9/L, PT, APTT and fibrinogen normal, DAT negative. A CBC a year ago was normal, with an MCV of 89 fL. The film shows many very small, dense, spherical red cells, red cells with small rounded buds at their edges, and occasional fragments. What is the most likely cause of the red cell changes?
1. AWarm autoimmune hemolytic anemia
2. BDisseminated intravascular coagulation
3. CHereditary spherocytosis under stress
4. DDirect heat damage to the red cell membrane
Show answerHide answer
Answer: D · Direct heat damage to the red cell membrane
Red cells heated above about 49 °C have their spectrin denatured, so the membrane buds off small spheres and fragments within hours of a severe burn. That gives microspherocytes, budding cells and fragments, a fall in MCV and a high MCHC, here alongside hemoconcentration from plasma loss. Hereditary spherocytosis is lifelong and would have shown on his normal CBC a year ago. The negative DAT argues against warm autoimmune hemolysis, and the normal platelet count, PT, APTT and fibrinogen argue against DIC. The damaged cells are cleared over the next day or two, so the Hb can fall sharply once fluid replacement corrects the hemoconcentration.
- A: The DAT is negative.
- B: The platelet count, PT, APTT and fibrinogen are all normal.
- C: Hereditary spherocytosis is lifelong; his CBC a year ago was normal.
Question 4 · Hard
A 56-year-old man with advanced alcoholic cirrhosis has worsening anemia, a raised indirect bilirubin and a raised reticulocyte count. His film shows many dense, contracted red cells bearing 3 to 10 sharp projections that vary in length and spacing. These cells are best described as:
1. ASpherocytes from immune membrane damage
2. BEchinocytes from prolonged sample storage
3. CAcanthocytes from excess membrane cholesterol
4. DSchistocytes from intravascular fragmentation
Show answerHide answer
Answer: C · Acanthocytes from excess membrane cholesterol
Dense cells with a few irregular, uneven projections are acanthocytes (spur cells). In severe liver disease, abnormal lipoproteins load the red cell membrane with free cholesterol, and the spleen then remodels and removes these cells, causing spur cell hemolytic anemia. Echinocytes have many short, evenly spaced projections and are often a storage or drying artefact. Schistocytes are fragments with sharp edges, and spherocytes are round with no projections.
- A: Spherocytes are round and smooth, without projections.
- B: Echinocytes have many short, regular projections.
- D: Schistocytes are fragments with straight, sharp edges.
Question 5 · Medium
A small cell with a round, very dense nucleus could be a small lymphocyte or an orthochromic normoblast. Which feature identifies the normoblast?
1. AA narrow rim of pale sky-blue cytoplasm
2. BA few azurophilic granules in the cytoplasm
3. CA visible nucleolus in the nucleus
4. DPink-orange cytoplasm like mature red cells
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Answer: D · Pink-orange cytoplasm like mature red cells
An orthochromic normoblast has nearly finished making hemoglobin, so its cytoplasm is the same pink-orange as nearby red cells, and its nucleus is small, round and almost black. A small lymphocyte has a thin rim of blue cytoplasm and clumped but less dense chromatin. Nucleated red cells are not white cells, so they are counted per 100 white cells and reported separately. Missing them inflates the lymphocyte count.
- A: A rim of sky-blue cytoplasm is typical of a lymphocyte.
- B: Azurophilic granules are seen in some lymphocytes, not normoblasts.
- C: Neither mature cell type shows a visible nucleolus.
Question 6 · Medium
A blood film from a patient with a hematocrit of 0.62 L/L comes out short and too thick to read. Which change in technique should correct this?
1. ACollect a fresh sample in heparin
2. BUse a larger drop of blood
3. CLower the angle of the spreader slide
4. DRaise the angle of the spreader slide
Answer and explanation in LearnFree account
Question 7 · Medium
On a blood film, rouleaux is distinguished from red cell agglutination by:
1. AClumps that persist in saline
2. BLinear stacks of cells, like coins
3. CClumps that disperse on warming
4. DIrregular, grape-like clumps of cells
Answer and explanation in LearnFree account
Question 8 · Hard
Several hand-stained blood films show fine, dark purple granules lying on red cells, on white cells and on the bare glass between cells. What is the most likely explanation and remedy?
1. ABasophilic stippling; report it with the film
2. BPappenheimer bodies; confirm with Prussian blue
3. CStain precipitate; filter stain, stop it drying
4. DPlatelet clumps; recollect the sample in citrate
Answer and explanation in LearnFree account
Question 9 · Easy
When a wedge blood film is made, the spreader slide is usually held at an angle of about:
1. A5 to 10 degrees
2. B30 to 45 degrees
3. C60 to 75 degrees
4. D90 degrees
Answer and explanation in LearnFree account
Question 10 · Hard
A film from a patient with a normal CBC shows teardrop-shaped red cells in one area only, and all their tails point in the same direction. The most likely explanation is:
1. AA film-spreading artefact
2. BBeta thalassemia major
3. CPrimary myelofibrosis
4. DMegaloblastic anemia
Answer and explanation in LearnFree account
Question 11 · Medium
In a two-step Wright stain, the cells take up the dyes and become colored when:
1. AThe stained film is left to air-dry
2. BThe methanol-based stain is first applied
3. CBuffer is added and the dyes ionize
4. DThe slide is rinsed with tap water
Answer and explanation in LearnFree account
Question 12 · Easy
A red cell with a slit-like, mouth-shaped area of central pallor is called a:
1. ASpherocyte
2. BStomatocyte
3. CTarget cell
4. DElliptocyte
Answer and explanation in LearnFree account
Question 13 · Hard
A trainee performs the differential only in the thick area of a wedge film, near where the drop was placed. Which bias is most likely?
1. AMore neutrophils and monocytes, fewer lymphocytes
2. BNo bias, only lower precision
3. CMore lymphocytes, fewer neutrophils and monocytes
4. DMore monocytes, fewer lymphocytes
Answer and explanation in LearnFree account
Question 14 · Medium
A sample from a patient with chronic lymphocytic leukemia produces so many smudge cells that the differential is unreliable. Which preparation step reduces smudging?
1. ACollecting the sample in heparin
2. BStaining with a more alkaline buffer
3. CAdding bovine albumin before spreading
4. DFixing the film in formalin vapour
Answer and explanation in LearnFree account
Question 15 · Medium
A basophil on a Wright-stained film has only a few dark granules and several clear, empty-looking spaces in its cytoplasm. The best explanation is that:
1. AThe film was fixed in methanol too long
2. BThe stain buffer pH was too alkaline
3. CIts granules are water-soluble and dissolved
4. DThe EDTA in the tube destroyed the granules
Answer and explanation in LearnFree account
Question 16 · Hard
A healthy 30-year-old man has hemoglobin 148 g/L (reference 130-170 g/L), MCV 89 fL (reference 80-100 fL), a normal reticulocyte count and a normal ferritin. About 60% of his red cells are oval to elongated. The most likely cause is:
1. AIron deficiency anemia
2. BPrimary myelofibrosis
3. CMegaloblastic anemia
4. DHereditary elliptocytosis
Answer and explanation in LearnFree account
Question 17 · Hard
A 50-year-old receiving filgrastim (G-CSF) after chemotherapy is afebrile with negative blood cultures. WBC is 28 × 10^9/L, and the film shows a left shift to myelocytes, heavy dark neutrophil granulation and Döhle bodies. What best explains these neutrophil changes?
1. AChronic myeloid leukemia
2. BAn overly alkaline stain buffer
3. CEffect of the growth factor treatment
4. DAlder-Reilly anomaly
Answer and explanation in LearnFree account
Question 18 · Medium
Films fixed from a methanol bottle left open all week show many red cells with sharp-edged, shiny, refractile clear areas. What is the most likely cause?
1. AUnfiltered stain forming precipitate
2. BWater absorbed by the methanol fixative
3. CA stain buffer with too low a pH
4. DGrease left on the glass slides
Answer and explanation in LearnFree account
Question 19 · Hard
A film made from blood left in a heparinized blood gas syringe shows a faint blue haze over the whole background and small clumps of platelets and white cells. The red cells are evenly spread. The most likely explanation is:
1. ACold agglutinins in the patient's plasma
2. BA stain buffer that is too acidic
3. CThe heparin anticoagulant in the syringe
4. DA paraprotein in the patient's plasma
Answer and explanation in LearnFree account
Question 20 · Hard
A film made from a 2-day-old EDTA sample from a patient on hemodialysis shows many red cells with 10 to 30 short, evenly spaced projections. What is the best next step?
1. AReport the cells as acanthocytes
2. BRestain the film with a more acidic buffer
3. CReview a film made from a fresh sample
4. DReport uremic burr cells without comment
Answer and explanation in LearnFree account
Question 21 · Easy
Romanowsky stains such as Wright and Giemsa are based on which pair of dyes?
1. ACrystal violet and safranin
2. BMethylene blue (azures) and eosin
3. CCarbol fuchsin and methylene blue
4. DHematoxylin and eosin
Answer and explanation in LearnFree account
Question 22 · Hard
A 3-year-old has hemoglobin 94 g/L (9.4 g/dL) and MCV 71 fL. The film shows coarse basophilic stippling in many red cells. Ferritin is within its reference interval and HbA2 is 2.7% (reference 2.0-3.3%). The child's eyes are lined daily with a traditional kohl powder. The most likely diagnosis is:
1. AAnemia of inflammation
2. BLead poisoning
3. CBeta thalassemia trait
4. DIron deficiency anemia
Answer and explanation in LearnFree account
Question 23 · Medium
Basophilic stippling seen in red cells on a Wright-stained film consists of aggregated:
1. ARibosomes (RNA)
2. BIron granules
3. CNuclear DNA fragments
4. DDenatured hemoglobin
Answer and explanation in LearnFree account
Question 24 · Medium
Thick and thin blood films are made for malaria. Why is the thin film fixed with methanol but the thick film is not?
1. AFixation is needed only for routine blood counts
2. BFixing the thin film lyses its red cells so parasites are easier to see
3. CThe thick film must also be fixed to see parasites
4. DIt keeps thin-film red cells intact; the unfixed thick film lyses
Answer and explanation in LearnFree account
Question 25 · Easy
Target cells (codocytes) are commonly seen in which conditions?
1. AThalassemia and liver disease
2. BHereditary spherocytosis
3. CDisseminated intravascular coagulation
4. DPrimary myelofibrosis
Answer and explanation in LearnFree account

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Peripheral smear: preparation, staining and morphology

A 56-year-old man with advanced alcoholic cirrhosis has worsening anemia, a raised indirect bilirubin and a raised reticulocyte count. His film shows many dense, contracted red cells bearing 3 to 10 sharp projections that vary in length and spacing. These cells are best described as:

A small cell with a round, very dense nucleus could be a small lymphocyte or an orthochromic normoblast. Which feature identifies the normoblast?

A blood film from a patient with a hematocrit of 0.62 L/L comes out short and too thick to read. Which change in technique should correct this?

On a blood film, rouleaux is distinguished from red cell agglutination by:

Several hand-stained blood films show fine, dark purple granules lying on red cells, on white cells and on the bare glass between cells. What is the most likely explanation and remedy?

When a wedge blood film is made, the spreader slide is usually held at an angle of about:

A film from a patient with a normal CBC shows teardrop-shaped red cells in one area only, and all their tails point in the same direction. The most likely explanation is:

In a two-step Wright stain, the cells take up the dyes and become colored when:

A red cell with a slit-like, mouth-shaped area of central pallor is called a:

A trainee performs the differential only in the thick area of a wedge film, near where the drop was placed. Which bias is most likely?

A sample from a patient with chronic lymphocytic leukemia produces so many smudge cells that the differential is unreliable. Which preparation step reduces smudging?

A basophil on a Wright-stained film has only a few dark granules and several clear, empty-looking spaces in its cytoplasm. The best explanation is that:

A healthy 30-year-old man has hemoglobin 148 g/L (reference 130-170 g/L), MCV 89 fL (reference 80-100 fL), a normal reticulocyte count and a normal ferritin. About 60% of his red cells are oval to elongated. The most likely cause is:

A 50-year-old receiving filgrastim (G-CSF) after chemotherapy is afebrile with negative blood cultures. WBC is 28 × 10^9/L, and the film shows a left shift to myelocytes, heavy dark neutrophil granulation and Döhle bodies. What best explains these neutrophil changes?

Films fixed from a methanol bottle left open all week show many red cells with sharp-edged, shiny, refractile clear areas. What is the most likely cause?

A film made from blood left in a heparinized blood gas syringe shows a faint blue haze over the whole background and small clumps of platelets and white cells. The red cells are evenly spread. The most likely explanation is:

A film made from a 2-day-old EDTA sample from a patient on hemodialysis shows many red cells with 10 to 30 short, evenly spaced projections. What is the best next step?

Romanowsky stains such as Wright and Giemsa are based on which pair of dyes?

A 3-year-old has hemoglobin 94 g/L (9.4 g/dL) and MCV 71 fL. The film shows coarse basophilic stippling in many red cells. Ferritin is within its reference interval and HbA2 is 2.7% (reference 2.0-3.3%). The child's eyes are lined daily with a traditional kohl powder. The most likely diagnosis is:

Basophilic stippling seen in red cells on a Wright-stained film consists of aggregated:

Thick and thin blood films are made for malaria. Why is the thin film fixed with methanol but the thick film is not?

Target cells (codocytes) are commonly seen in which conditions?