A 10-month-old girl has had two mild ear infections and is otherwise thriving. Her blood count at 2 months of age was normal. Twice-weekly counts over 6 weeks show an absolute neutrophil count between 0.2 and 0.5 × 10^3/µL [0.2-0.5 × 10^9/L] (reference for age 1.0-8.5 × 10^3/µL), with a mild monocytosis and normal hemoglobin and platelet counts. The marrow is normocellular, with myeloid cells maturing normally through the metamyelocyte stage but few segmented neutrophils, and there is no arrest at the promyelocyte stage. Granulocyte antibody testing detects anti-HNA-1a. The most likely diagnosis is:

Autoimmune neutropenia of infancy

Alloimmune neonatal neutropenia

Which blood film feature favors a reactive lymphocytosis over a lymphoid neoplasm?

A range of lymphocyte sizes and shapes

A uniform population of identical cells

Blasts with fine chromatin and nucleoli

Toxic granulation, Döhle bodies and cytoplasmic vacuoles in neutrophils most often indicate:

Severe bacterial infection or sepsis

A 29-year-old has had fever and fatigue for 3 weeks, with no sore throat and a mildly raised ALT. WBC is 11.2 × 10^3/µL (11.2 × 10^9/L) with 62% lymphocytes, many of them reactive. Two heterophile tests, EBV viral capsid antigen IgM and IgG, and an HIV antigen/antibody test are all negative. The most likely cause is:

Early Epstein-Barr virus infection

An unvaccinated 3-month-old has a paroxysmal cough. The WBC is 42.0 × 10^3/µL (42.0 × 10^9/L), with 78% small, mature-looking lymphocytes, some with cleaved nuclei. What is the most likely cause?

B-cell acute lymphoblastic leukemia

Benign leukocyte disorders: myeloid and lymphoid

13 ASCP MLS practice questions on Benign leukocyte disorders: myeloid and lymphoid, part of Hematology. The first 13 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 10-month-old girl has had two mild ear infections and is otherwise thriving. Her blood count at 2 months of age was normal. Twice-weekly counts over 6 weeks show an absolute neutrophil count between 0.2 and 0.5 × 10^3/µL [0.2-0.5 × 10^9/L] (reference for age 1.0-8.5 × 10^3/µL), with a mild monocytosis and normal hemoglobin and platelet counts. The marrow is normocellular, with myeloid cells maturing normally through the metamyelocyte stage but few segmented neutrophils, and there is no arrest at the promyelocyte stage. Granulocyte antibody testing detects anti-HNA-1a. The most likely diagnosis is:
1. AAutoimmune neutropenia of infancy
2. BCyclic neutropenia
3. CAlloimmune neonatal neutropenia
4. DSevere congenital neutropenia
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Answer: A · Autoimmune neutropenia of infancy
A neutropenia that develops after a normal count in early infancy, with only mild infections, a marrow that lacks mainly the mature segmented cells, and an antibody to a neutrophil-specific antigen (HNA-1a) is primary autoimmune neutropenia of infancy. The child's own antibodies coat mature neutrophils, which are removed in the spleen, while the marrow keeps producing them. It is usually found between about 5 and 15 months of age and resolves on its own in most children within 2 to 3 years. Severe congenital neutropenia starts at birth with serious infections and an arrest at the promyelocyte stage, and cyclic neutropenia returns to normal between nadirs that come about every 21 days. Alloimmune neonatal neutropenia comes from maternal antibody, is present from birth and clears within the first months.
- B: Twice-weekly counts stay low throughout, without the recovery between nadirs seen in cyclic neutropenia.
- C: Alloimmune neutropenia is present from birth and clears early; her count was normal at 2 months.
- D: Severe congenital neutropenia starts at birth with serious infections and a promyelocyte arrest.
Question 2 · Medium
Which blood film feature favors a reactive lymphocytosis over a lymphoid neoplasm?
1. AA uniform population of identical cells
2. BBlasts with fine chromatin and nucleoli
3. CA range of lymphocyte sizes and shapes
4. DMany smudge cells
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Answer: C · A range of lymphocyte sizes and shapes
Reactive lymphocytes form a spectrum: small, large, plasmacytoid and immunoblastic forms are mixed together, because many clones respond at once. A neoplasm usually gives a monotonous population of similar cells from one clone. Many smudge cells suggest CLL, and blasts with nucleoli suggest acute leukemia. Flow cytometry can show whether the population is polyclonal or monoclonal when the film is unclear.
- A: A uniform population suggests a single clone, as in lymphoid neoplasms.
- B: Blasts with nucleoli suggest acute lymphoblastic leukemia.
- D: Many smudge cells suggest chronic lymphocytic leukemia.
Question 3 · Easy
Toxic granulation, Döhle bodies and cytoplasmic vacuoles in neutrophils most often indicate:
1. ASevere bacterial infection or sepsis
2. BVitamin B12 deficiency
3. CChronic lymphocytic leukemia
4. DAllergic drug reaction
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Answer: A · Severe bacterial infection or sepsis
During severe infection or inflammation, neutrophils are released quickly from the marrow and show toxic changes. Toxic granulation is persistence of dark-staining primary granules, Döhle bodies are pale blue patches of rough endoplasmic reticulum, and vacuoles reflect phagocytosis. These changes often come with a left shift and support sepsis. Vacuoles alone can be an artifact of EDTA blood stored too long, so films should be made from fresh blood.
- B: B12 deficiency causes hypersegmented neutrophils, not toxic changes.
- C: CLL is a lymphocyte neoplasm and does not cause these neutrophil changes.
- D: Allergic reactions cause eosinophilia rather than toxic neutrophil changes.
Question 4 · Hard
A 29-year-old has had fever and fatigue for 3 weeks, with no sore throat and a mildly raised ALT. WBC is 11.2 × 10^3/µL (11.2 × 10^9/L) with 62% lymphocytes, many of them reactive. Two heterophile tests, EBV viral capsid antigen IgM and IgG, and an HIV antigen/antibody test are all negative. The most likely cause is:
1. AChronic lymphocytic leukemia
2. BBordetella pertussis infection
3. CEarly Epstein-Barr virus infection
4. DCytomegalovirus infection
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Answer: D · Cytomegalovirus infection
Cytomegalovirus is the most common cause of heterophile-negative mononucleosis in adults, typically with prolonged fever, mild hepatitis and reactive lymphocytes but little pharyngitis or lymph node swelling. Negative EBV viral capsid antigen IgM and IgG exclude current or past EBV infection, because these antibodies are already present when symptoms start. Acute HIV infection and toxoplasmosis can look similar, which is why HIV testing is part of the workup. CMV IgM or CMV PCR confirms the diagnosis.
- A: CLL occurs in older adults and shows small mature cells and smudge cells.
- B: Pertussis gives small mature lymphocytes in infants, not reactive lymphocytes in adults.
- C: EBV capsid antibodies are present when symptoms start, so negative results exclude EBV.
Question 5 · Medium
An unvaccinated 3-month-old has a paroxysmal cough. The WBC is 42.0 × 10^3/µL (42.0 × 10^9/L), with 78% small, mature-looking lymphocytes, some with cleaved nuclei. What is the most likely cause?
1. AChronic lymphocytic leukemia
2. BBordetella pertussis infection
3. CInfectious mononucleosis
4. DB-cell acute lymphoblastic leukemia
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Answer: B · Bordetella pertussis infection
Pertussis toxin stops lymphocytes from leaving the blood, so a marked lymphocytosis of small, normal-looking lymphocytes develops, sometimes above 50 × 10^3/µL. Some of the cells have cleaved (clefted) nuclei. Infectious mononucleosis gives large reactive lymphocytes in older children and adults, and CLL does not occur in infants. Acute lymphoblastic leukemia shows blasts with fine chromatin, not mature cells.
- A: CLL is a disease of older adults and does not occur in infants.
- C: Infectious mononucleosis gives large reactive lymphocytes, not small mature ones.
- D: ALL shows blasts with fine chromatin and nucleoli, not mature lymphocytes.
Question 6 · Hard
WBC 3.0 × 10^3/µL (3.0 × 10^9/L): neutrophils 22%, lymphocytes 68%, monocytes 8%, eosinophils 2%. Using ASCP reference ranges, how is this best interpreted?
1. AAbsolute neutropenia and absolute lymphocytosis
2. BAbsolute neutropenia and absolute lymphopenia
3. CAbsolute lymphocytosis with a normal neutrophil count
4. DAbsolute neutropenia with a relative lymphocytosis
Answer and explanation in LearnFree account
Question 7 · Hard
A healthy 34-year-old man of West African ancestry, taking no medicines, has an absolute neutrophil count of 1.2 × 10^3/µL (1.2 × 10^9/L) on three occasions, with no infections and a normal hemoglobin, platelet count and film. His red cells type Fy(a-b-). What is the most likely explanation?
1. ADrug-induced immune neutropenia
2. BEarly acquired aplastic anemia
3. CCyclic neutropenia (ELANE mutation)
4. DDuffy-null associated neutrophil count
Answer and explanation in LearnFree account
Question 8 · Medium
A differential shows WBC 18.5 × 10^3/µL (18.5 × 10^9/L): segmented neutrophils 68%, bands 18%, metamyelocytes 4%, lymphocytes 8% and monocytes 2%, with toxic granulation and no nucleated red cells. This is best described as:
1. AA neutrophilic leukemoid reaction
2. BChronic neutrophilic leukemia
3. CNeutrophilia with a left shift
4. DA leukoerythroblastic reaction
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Question 9 · Hard
A 70-year-old with a perforated bowel has WBC 64.0 × 10^3/µL (64.0 × 10^9/L). The film shows segmented neutrophils, bands, metamyelocytes and a few myelocytes, with toxic granulation and Döhle bodies, no basophilia and a normal platelet count. The spleen is not enlarged. What is the most likely diagnosis?
1. ANeutrophilic leukemoid reaction
2. BChronic myeloid leukemia, chronic phase
3. CLeukoerythroblastic reaction
4. DAcute myeloid leukemia
Answer and explanation in LearnFree account
Question 10 · Easy
Epstein-Barr virus, the cause of infectious mononucleosis, mainly infects which blood cells?
1. ANatural killer cells
2. BB lymphocytes
3. CMonocytes
4. DCytotoxic T cells
Answer and explanation in LearnFree account
Question 11 · Medium
An injection of epinephrine raises the neutrophil count within minutes, mainly by:
1. AIncreasing marrow production of neutrophils
2. BLengthening the lifespan of blood neutrophils
3. CReleasing band forms from the marrow reserve
4. DShifting marginated cells into the circulating pool
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Question 12 · Medium
In infectious mononucleosis, most of the reactive lymphocytes on the film are which cells?
1. ANatural killer cells
2. BEBV-infected B cells
3. CCD8+ cytotoxic T cells
4. DNeoplastic lymphoblasts
Answer and explanation in LearnFree account
Question 13 · Hard
A 61-year-old woman treated for breast cancer 4 years ago now has anemia and back pain. WBC is 8.9 × 10^3/µL (8.9 × 10^9/L), and the film shows nucleated red cells, teardrop cells, myelocytes and metamyelocytes. This picture most likely reflects:
1. ABone marrow metastases
2. BOverwhelming bacterial sepsis
3. CA leukemoid reaction
4. DMegaloblastic anemia
Answer and explanation in LearnFree account

Benign leukocyte disorders: myeloid and lymphoid

Which blood film feature favors a reactive lymphocytosis over a lymphoid neoplasm?

Toxic granulation, Döhle bodies and cytoplasmic vacuoles in neutrophils most often indicate:

An unvaccinated 3-month-old has a paroxysmal cough. The WBC is 42.0 × 10^3/µL (42.0 × 10^9/L), with 78% small, mature-looking lymphocytes, some with cleaved nuclei. What is the most likely cause?

WBC 3.0 × 10^3/µL (3.0 × 10^9/L): neutrophils 22%, lymphocytes 68%, monocytes 8%, eosinophils 2%. Using ASCP reference ranges, how is this best interpreted?

A healthy 34-year-old man of West African ancestry, taking no medicines, has an absolute neutrophil count of 1.2 × 10^3/µL (1.2 × 10^9/L) on three occasions, with no infections and a normal hemoglobin, platelet count and film. His red cells type Fy(a-b-). What is the most likely explanation?

A differential shows WBC 18.5 × 10^3/µL (18.5 × 10^9/L): segmented neutrophils 68%, bands 18%, metamyelocytes 4%, lymphocytes 8% and monocytes 2%, with toxic granulation and no nucleated red cells. This is best described as:

Epstein-Barr virus, the cause of infectious mononucleosis, mainly infects which blood cells?

An injection of epinephrine raises the neutrophil count within minutes, mainly by:

In infectious mononucleosis, most of the reactive lymphocytes on the film are which cells?

A 61-year-old woman treated for breast cancer 4 years ago now has anemia and back pain. WBC is 8.9 × 10^3/µL (8.9 × 10^9/L), and the film shows nucleated red cells, teardrop cells, myelocytes and metamyelocytes. This picture most likely reflects: